Bill:

The pony bought from Bill Ferney in Bree. He had a talent for finding paths and became friends with Samwise Gamgee. Bill carried their packs from Bree to Rivendell and then to the East Gate of Moria. The Hobbits found him again in Bree on their return.
When they met his former owner in the Shire, Bill kicked him.

Bëornings:

Men, ruled by the descendants of Bëorn. They lived between the Misty Mountains and Erebor and Dale.

Bumpkin:

One of the ponies belonging to Merry. Bumpkin was named such during the hobbits stay with Tom Bombadil. When the Prancing Pony Inn was raided, the ponies fled to Bombadil, who later sent them to Butterbur.

The Lord of the Rings
The Silmarillion
The Unfinished Tales
The Hobbit
The Complete Guide to Middle Earth by Robert Foster