So i figured to make this due to that fact the yellow garden spiders in the web challenges do not count as discovering them. Which has made them hard to find.
So here are some locations of them outside of the challenges. Any other one you are struggling with, let me know and ill see if i can be of any help!

Number one is where it triggered for me.
One of the locations i had found one is new the new hive, towards the arch and water fountain. It was on the floor, near some mushrooms. See the photo below to reference where it is to be found.
https://steamuserimages-a.akamaihd.net/ugc/1803122888329036601/017FF64F7B42F9873ECEAB0C9C42E42F39CDB5AF/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

Second locations i found them, is in the same enclourser as the first hive (in with the dear). There is a spider a little web (not a challenge) on the fencing around a tree. The image is dark, so sorry about that. But i hope you can make it out enough to find it.
https://steamuserimages-a.akamaihd.net/ugc/1803122888329040812/15AA46D95B993E26788AEBB78D48564A59328E4F/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

Lastly where i had found one is on the stage in the park. on the left of the stage is letters, next to the letter (C i believe) is a spider in a web that is not part of a challenge. Thus should trigger a discovery.
https://steamuserimages-a.akamaihd.net/ugc/1803122888329046522/AEE2B3454E193D88EB8890FB728ED08755B6F2AC/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false