I am interested in getting another pet but what kind?

my family and I have dogs, cats, a bunny, and i have a lovebird. I've had all kinds of rodents,fish, and two parakeets before and have a ton of animal experience with fostering. I have some extra space and time and really enjoy taking care of animals. Lately i've thought it over and i am thinking of possibly adding a friend to the group. I thought about a cockatiel but i think that might be a little bit too much work so now i am thinking about a hamster or a mini fish tank for my room. Any other pets who are easy to take care of and make great pets? and any certain types of hamsters?(i dont want to get a russian dwarf because i've already had a few. I was thinking winter white hamster?) would it be better to get two hamsters? THANKS and let me know if you have any other pet ideas. i aprreciate all answers!