There is plenty of free assets on booth. But some free things are listed as having a price of 100-500yen because they have donation options so adjust the price range for best results.
https://booth.pm/en/browse/3D%20Environments%20%2F%20World?max_price=0
https://booth.pm/en/search/udon?max_price=0
Or use this for game rips https://www.models-resource.com/
These are just some things I've bought or found, if anyone has more world assets or tutorials to contribute please do.
Assets
https://ambientcg.com/
https://booth.pm/en/items/1969082
https://booth.pm/en/items/1677650
https://booth.pm/en/items/3406912
https://animusvr.booth.pm/items/5111343
https://booth.pm/en/items/5111820
https://booth.pm/en/items/4524875
https://booth.pm/en/items/4380444
https://booth.pm/en/items/2579880
https://booth.pm/en/items/1680527
https://booth.pm/en/items/1581740
https://booth.pm/en/items/3788640
https://booth.pm/en/items/4190722
https://booth.pm/en/items/3777205
https://booth.pm/en/items/4171276
https://booth.pm/en/items/2658237
https://booth.pm/en/items/3728854
https://booth.pm/en/items/4870627
https://booth.pm/en/items/3802269
https://www.deviantart.com/ketokeas/art/MMD-DL-Winter-Park-Stage-573322335
https://bowlroll.net/file/181121 https://files.catbox.moe/8o03j0.rar
https://booth.pm/en/items/2663194 https://files.catbox.moe/8t7tw2.zip
https://www.patreon.com/posts/beautiful-sky-35667377 https://files.catbox.moe/i3f93b.unitypackage
https://www.patreon.com/posts/32030551 https://files.catbox.moe/w80uxs.unitypackage
https://www.patreon.com/posts/32637838
https://paveloliva.gumroad.com/l/buildify
https://booth.pm/ja/items/1968293 https://mega.nz/file/iIgCXITJ#WBgTi43QDPpnmMOSmyTnlwRn-r1-pg6rAe95BCoyTl0
https://github.com/vvoovv/blosm
Games
https://github.com/pool-parlor/pool-parlor-table
https://booth.pm/en/items/2766178 https://files.catbox.moe/7xlk6k.zip
https://booth.pm/en/items/3115743 https://files.catbox.moe/4uqa2j.zip
https://booth.pm/en/items/3637711 https://files.catbox.moe/cm23yu.zip
https://booth.pm/en/items/3466984 https://files.catbox.moe/sbh3zl.zip
https://booth.pm/en/items/3060394
https://booth.pm/en/items/3061165
https://booth.pm/en/items/3062043 https://files.catbox.moe/qbaw7y.zip
https://booth.pm/en/items/3060872 https://files.catbox.moe/qgio5c.zip
https://booth.pm/en/items/3075449 https://files.catbox.moe/3kgyr1.zip
Tutorials
From the OP https://rentry.org/4tzqs
https://creators.vrchat.com/
https://www.youtube.com/watch?v=uLi52YrrDmY&list=PLPdWkxUSZ65Fp6ICrU7mIq1znAfPwMhNZ
https://www.youtube.com/@VowganVR/videos
https://twitter.com/janvandenhemel
https://www.youtube.com/watch?v=U1f6NDCttUY&list=PL4Dq5VyfewIxxjzS34k2NES_PuDUIjRcY