Acceptable ways to get recommendation from /a/
Asking directly in obscure/dedicated fanbase threads
Feel free to add your own
Lurking because your thread got deleted
Basically every thread that isn't discussing current anime/manga or an image dump could be boiled down to a rec thread from an outsider perspective. It's an acceptable way to discover new titles, commonly known as "lurking."
show you wish you could forget and watch again
what does X the best?
you can't name a better x then y
harem threads - pretty light on discussion but get passes by mods as they are like 3x3s that fall into the "should generate discussion but rarely do" category
probably more types that don't come to mind that should just be reported and deleted as the OP is clearly not worth a fuck