I've been collecting minis and smalls for a few years now, and I'll start with my Grace Stamile minis with blooms registered at 3" or under. Most of these are diploids, except for Grace's BROADWAY series which are tets.
BLUE ALERT - 2.87" blooms
BROADWAY BLOODSPORT - 2.85"
BROADWAY CHERRY BLAST - 2.85"
BROADWAY ELF - 2.75"
BROADWAY LEGEND - 2.87"
BROADWAY PLAYER - 2.87"
CHILD OF ATLANTIS - 3"
ELFIN MAGIC - 3"
ELFIN REFLECTION - 2.87"
GOT THE BLUES - 2.87"
HONKY TONK BLUES - 3"
LITTLE BLOOM RIDER - 2.85"
LITTLE LEPRECHAUN - 2.87"
LITTLE MENEHUNE - 2.5"
LITTLE MISS INDEPENDENT - 2.5"
LITTLE MUCHA MINTO - 2.5"
LITTLE PETER PIPER - 3"
LITTLE RED FLIRT - 2.75"
LITTLE SURFER GIRL - 2.5"
TINY FIRECRACKER - 2.25"
Even though these are all registered at 3" or under, many of mine seem to have larger blooms, probably due to our climate.