I don’t know if this idea could be transformed into some type of sticky but I imagine that there are a lot of users that have created expression maps or are needing one. It can be a time consuming task to create them. Sharing them with each other on the forum seems like a good idea. There are currently list posted here and there but updating web pages also takes time.
Personally I would love it if someone had an expression map for Session Horns Pro:
https://www.native-instruments.com/en/products/komplete/cinematic/session-horns-pro/
Expression Maps list by Steinberg:
https://www.steinberg.net/en/support/content_and_accessories/expression_maps_for_vst_expression.html
Expression Maps list by Spitfire Audio:
https://spitfireaudio.zendesk.com/hc/en-us/articles/360006315094-List-of-Expression-Maps