I'm running out of the things to say;
This is just "Side" activities or hidden/semi-hidden stuff in the game.

After you done [Tycoon Wil] almost any time you have fully functioning party (or, sometimes, even 1 character, like Rich) you can re-visit Weissland.

There are three major incentives in doing so:

1. Buy another Hot Stone (you can never have enough hotstones)
2. Stat-spark some weaker characters on Polar Drakes (and, if you are lucky, get some loot along)
3. Re-summon and fight the Megalith Beast.

Most important would be, of course, Beast itself.
He has relatively big spark, is a party battle, has big HP pool (which allows you to wail on him for quite a long time, especially if you give your party low-attack weapons like Oak Staffs. More hits = more chances to spark!), is a sorta good post-battle sparker, and most importantly he is not really dangerous once you deal with the adds. He does *not* resummon them.
So get yourself some armor, grab regeneration+stone armor (and Guard Beast if you want to be very safe) + permanence and hit cross for 20 minutes hoping for spark.

He also drops abysmal accessory. Yay.

Again, once you've finished the Laub quest (which is also Tycoon Wil), you will be given access to it just as with Vogelang and so on.
The only interesting thing you can do here is Dead (or Ghost) Tower

So once you get to Laub go through east exit and you arrive at the tower.

There are 3 major objectives; you can do them in any order ('cept Anima Ghoul) and you can leave whenever you want. Tower will not reset progress on quests and bossess/loot will not respawn until NG+

Consider equipping Deadstones on your characters, undead enemies love to Deathblow.

1.[Main Quest: Elven Lyre]

Rush trough the tower to the top.
Activate organ.
Move screen backwards.
Inspect the stupid interesting-looking statue in the middle of the room.
>>>group fight, ghouls
Go down and move through the fenced gate (or don't, that opens up another fight).
Touch an Orb on the pedestal.
>>>Group fight with Ghosts
Return to the previous screen.
Enter the middle door.
RUSH (CCW) towards the bottom exit (on the south).
>>>Enemies will jump from the paintings and commit pursuit, potentially catching you. Nothing too bad though, usual ghouls and/or occasional ghost.
<<<if you did not go to orb you'll be sucked into painting for Demongrass boss fight. Nothing good drops from it and as a boss it is kinda letdown>>>
Move to the statue with glowing eyes, but do not touch/inspect it.
< QUICKSAVE >
Touch the Statue
>>> Gargoyle boss fight. Now this is a bit tougher. Make sure you have Recovery Breath on at least two characters, Stone Armor, Regen and some form of Defence Down (Nutcracker). Just slap it until it dies and dispel your party members as necessary.
Once it dies hope it drops Blackstone armor.
It didn't? Well too bad, load your QS and go again!
Consider loading quick save to get Blackstone. What do you mean consider just do it over and over!
Return to organ room and run through the North exit.
Voila, [Elven Lyre].

2. [Secret (kinda) Boss: The Lich]

In order to trigger it you need to fight specific enemies (some are hidden).
Assuming you go from the bottom of the tower.
First needed enemy is the twins on the screen with the outside terrace.
>>>Ghouls and more ghouls
Once you get them both a bunch of birds will spawn, get those too.
>>>Bunch of random monsters, nothing too bad.
Once done go to the room with the stupid interesting statue.
Inspect the painting east of it (under the stairs).
>>>OH GOD NOT THE BERRIES
Once done go north (not up the stairs) and inspect space between bookshelves.
Bug enemy will spawn for you to deal with.
>>>Ant Commander. Can be a bit tough, but has quite a spark in it.
Once done exit south.
Now next to the north exit there is a ladder, you can climb it and get Ark Stone, but also cause slime to fall on you.
>>>Slimes. Can be tough, but also can be Deathblown. The only one that is dangerous has AoE Cripple, so have Recovery Breath at the ready.
Once done go down to the fence gate. Do not exit.
See that transparent skeleton? That's the Lich.
Quicksave.
RUN AT IT WOOO (standing under the east alcove works as well).
>>>
Lich & 2 High Disciples.
Okay, I will not tell you how to do this fight, but he is formidable and do not listen to anyone who tells you otherwise.
Suggestions would be:

For defence:
Equip at least two of your party members with Deadstones. Falling to deathblow can be annoying.
Make sure you have water tools or Life Water on everyone or at least two party members.
Soul Hymn is great to have; if you don't have access to it get Regeneration.
Guardian Beast on everybody.
Mindscape.
Permanence to lock your buffs.
At least two Recovery Breath available.
Shields or Flame resistace (hotstones!) is recommended.

For offence:
If you have character with high Tone - Hymnal is good choice.
Bring someone with Nutcracker to lower defence.
High level Spear user is a very good choice to have in your party - do the Beast Lightning to lower magic def, then switch to Thousand Cross (or any Hybrid spear art if you lack TC).
Focus one at a time.

For beating it you'll get achievement and Cinderforged Sword.

3.Third and Important thing: The Anima Ghoul
(can be done after finishing the Lyre)
Accessed via east door on the first screen.
QUICKSAVE
Go to the middle of glowing platform.
>>>ANIMA GHOUL
Duel.
This thing has high enough spark to get you Soul Hymn with Rich.
You know what to do.

That's it, you done with Laub tower. Congratz!

BURY MY BODY IN VOGELANG CANYONS FOR THERE I LIVED.

Uhm, yes, [Vogelang].
Accessible once you are done with Desert Megalith.
There aren't much to do, but all of the things are important.

The City.
1. On the right side there is tool scrapper. Well, this is irrelevant now that you can scrap anywhere. We'll miss you ;w;.

2. On the left side, in the building you can buy various (and usually good!) things to aid you in the adventure. Also, there is a Chip-to-Credit trader and, most importanly the Custom tools maker.

I covered the things he sells in the item guide so you can refer there for exact stats. Worst thing he sells is "okay" is most are good or close to being best in their categories.
Now, how to unlock them.

First, you need Chip circulation. It increases every time you scrap an item, directly or through the NPC or convert Chips to Credits.
The Custom tool creation used to lower chip circulation, but I am not sure if it does now.

Second, you need certain amount of levels in different categories. It does not need to be on the same character, but it does not count inherited stats (need to confirm).

The loot is as follows:
Carthel: 10000 Circulation, Stone 25, Sword 25 // costs 2000 Credits / 1000 Chips
Hawk Wind: 9000 Circulation, Beast 25, Axe 25 // costs 1500 Credits / 1000 Chips
Limstokes: 8000 Circulation, Water 25, Staff 25 // costs 1000 Credits / 1000 Chips
Babrashka: 9000 Circulation, Tree 25, Spear 25 // costs 1500 Credits / 1000 Chips
Beast Dancer: 12000 Circulation, Beast 25, Bow 25 // costs 2000 Credits / 1000 Chips
Pan Flute: 1000 Circulation, -- // costs 500 Credits / 100 Chips
Soul Crystal: 5000 Circulation, -- // costs 500 Credits / 200 Chips

For getting every Custom Tool you will get an Achievement.

The Chip Circulation/Infinite Money trick
Go to Laubholz shop.
Find Oak Staff.
It costs 50 creds in Laub's shop and turns to 10 chips.
10 staffs cost 500 creds
10 staffs turns into 100 chips
100 chips turns into 550 creds
and once you have more money
50 staffs cost 2500 creds
50 staffs turns into 500 chips
500 chips turns into 3000 creds
Capitalism Ho!

The Canyons
First, to get best seed exit the city and check what you have on the first screen.
If there Rock Rhino sprite + Bug sprite + Mandragora sprite you got good seed. (btw those are Horned Buffalo, Armored Beetle and Demongrass (I think...) respectively).
To get to the LOOP:
>clean the first screen
Exit south.
Ignore the mob.
Exit North-East.
>Rock Rhino sprite is Horned Buffalo
Exit East
>Bug in the middle is Grass Dancer (Garms can be rarely found in any bug sprite on this screen)
---Loop begins---
Exit lower East
>Rock Rhino sprite is Horned Buffalo
Exit West
Exit South
Rock Rhino sprite x2 is Horned Buffalo
Bug sprite is Armored Beetle
Return East
---Now you can go lower East again, the Horned Buffalo respawned---
Exit lower East
>Rock Rhino sprite is Horned Buffalo
---The Horned Buffalo and Armored Beetle respawned---
Exit West
Exit South
Rock Rhino sprite x2 is Horned Buffalo
Bug sprite is Armored Beetle
Return East
...
...
...
...
...
Once you done or (nearly) run out of WP/SP go (assuming you exited East):
Exit upper West
>Here will be respawned horned Buffalo
Exit South
Exit North-West
>First screen with HB/AB/DE
Exit West to re-enter the city and go rest at the inn.
Repeat!

Yay, we done with VogCan! You can never be done with VogCan...

I have no idea why I keep writing these; most of info can be found over the boards; but I guess congretating these in one place sorta helps?
As usual kindly point out any mistakes or misspells in the guide, I will try to fix it. Suggestions are welcome as well.

Cheers,