>>2684852>>2684903pic related is what i use mostly. its just called bukkake, each one has bones so you can manipulate them i dont remember where i found it, but i do know i found it through a google search so its most likely easy to find. readme says the creators name is Asanu if that helps.
https://w.atwiki.jp/beamman/ is an archive of beammans effects. there are quite a few liquid effects that may suit your needs. however they are moving effects, not static models like pic related. so they spray out and disappear after a set time. still very useful
https://mmda.booru.org/index.php?page=post&s=view&id=2734 going by the picture it looks like there is only one, but there are actually 10 included in the file. they are sperm/saliva type models with physics.
i was also looking for jizz effects for a long time and no one here seemed to know where to find any. so i hope i was able to help.