Long time 5e DM, switched to 2e about 6 months ago and have been running an AP in that time. However I have come to a spot in the adventure with some wiggle room and I want to homebrew a few side quests and such. However, I'm fairly overwhelmed with the sheer amount of monsters, so what are your go-tos for picking the right one for the job? For 5e I had donjon and aidnd.

Also... Treasures? How do you choose for those? Gatewalkers feels fairly sparse on giving money and magic items or trinkets to the characters, so I'd like to look at a few that might work... Do I just hop on AoN and scroll through everything?