https://www.tonytextures.com/ - textures

https://skalgubbar.se/ - diverse cutout people

https://www.mrcutout.com/ - png files

https://www.gobotree.com/ - scarily real 3D png people

http://www.nonscandinavia.com/ - diverse cutout people

https://pimpmydrawing.com/ - png people (silhouetted)

http://elderlyentourage.com/ - elderly cutout people

http://www.escalalatina.com/ - diverse cutout people

http://artcutout.studioalternativi.co.il/ - png files

http://www.cutoutlife.com/ - png files

https://www.turbosquid.com/ - models of vegetation to export at the angle of your choosing as a png

https://immediateentourage.com/ - png files

https://www.toffu.co/ - artsy silhouettes, furniture, plants, etc.

https://www.pngitem.com/

https://www.poliigon.com/ - greatly mapped materials for renders

https://www.cad-blocks.net/

https://www.revitcity.com/index.php

https://www.bimobject.com/en-us

https://www.linecad.com/

https://flyingarchitecture.com/

https://flyingarchitecture.com/materials - rhino texture/materiality resources

https://snazzymaps.com/

https://cadmapper.com/

https://www.textures.com/ - database of JPG textures

https://visualizingarchitecture.com/ - tutorials

https://www.dimensions.guide/classifications/humans - dimensions guide

https://thenounproject.com/ - icons and logos free for download

https://xoio-air.de/ - many resources

https://www.arch-vizz.com/ - tutorials, png resources, etc.