https://www.desidime.com/discussions/which-is-one-is-best-and-why?page=1#post_8992223
All are different things. Onecard is full fledged credit card with Bank tie up.
rest i have not used but from other posts here it seems
Jupiter and fi give accounts and a debit card.
postpe and slice have launched new products which are complicated to explain for me. Someone else can explain better. They are not credit card tho.