Me and my friend started an SMP not so long ago and we only have 2 auto farms and the basic manual farms and one contraption, our auto farms are a beef/leather farm and a semi automatic crop farm, and a super smelter; what farms or contraptions should we have in this stage. I'm willing to elaborate more on the progress of the SMP in the comments of this thread
Any farm that can get you XP quickly is good (ex. mob farms or trading halls), but make sure that if it on an SMP you don't make something that'll lag everyone else's game. More specifically, don't make a super powerful farm for a server you'll know will cause it to crash in some form.