Dachshunds are quite entertaining little dogs! They come in Miniature and Standard size (11 lbs and under, and then over 11 lbs, but most standards are around 20 lbs). They also come in three different coat types: wirehair, longhair, and smooth. Smooth is easiest to care for, although longhairs generally don't have THAT much hair, and I wouldn't consider them to require excessive grooming. My own only needs to be brushed once or twice a week for about 5 or 10 minutes. Wirehairs do require professional grooming unless you want to buy all the tools and equipment, which is quite expensive. Dachsies are very good companions, and though they can be difficult to train, they are such sweeties they're worth the effort.
I would also look into breeds such as Toy Fox Terrier or Rat Terriers, Jack Russel Terriers, Miniature Bull Terriers, Pembroke Welsh Corgis, Basset Hounds, Scottish Terriers (but they will require grooming), or Miniature Schnauzers (which will also require grooming). All these dogs stand out to me as having a unique look and personality. Keep in mind that terriers are feisty little dogs and require exercise, even if that just means a lengthy session of fetch in the living room. They will also require the right motivation for training; I would suggest positive reinforcement methods. You might check out a local shelter or humane society, as many have purebreds to adopt. Good luck!