Please make Far Cry 3 on uplay because i cant play 
Welcome to the community. 
As far as I am aware, there are no plans to develop any Far Cry 3 trainers further, maybe unless the game updates (unlikely).
Far Cry 3 was released in 2012, it’s now considered “old”. The majority of the playerbase has moved on, so getting enough requests for a trainer to be made will be difficult (you need to vote for trainers via the WeMod desktop app, not request them here in the forum).
Far Cry 6 is coming soon. The Far Cry fans are likely saving up their WeMod vote tokens for this game once released. I’d suggest seeing if you can get a refund from Uplay and get the game on Steam instead, which we already have a trainer for.