Bullywug

Bullywugs are amphibious humanoids similar in appearance to frogs or toads.

Description
Bullywugs can communicate simple concepts to frogs and toads using croaking, can make a long jump up to 20 feet and a high jump up to 10 feet, with or without a running start, and can breathe air and water. They also have advantage on Dexterity (Stealth) checks made to hide in swampy terrain. The bullywugs can make two melee attacks: one with its bite and one with its spear or another simple weapon like a club.

Bullywugs see froghemoths as gods and put their best efforts to provide them with food, fanatically protect them from harm, and try to ensure that any young froghemoth reaches maturity. They can communicate with one another by croaking.

Known bullywugs
Bullywug tribes inhabit the K'Tawl Swamp at the edges of Stilben. A clan of bullywugs is settled in a cave of the Brokenveil Marsh, domesticated a number of giant toads, and daily sends hunting and raiding parties into the marsh, riding giant toads.

There are multiple bullywugs who live in the garden of the Folding Halls of Halas and following the lead of a froghemoth. When the froghemoth ambushed Nott and initiated a fight with the Mighty Nein, it croaked attracting the frog-like creatures to support it. Caleb cast Fireball and his newly developed spell Widogast's Web of Fire, hitting the huge frog creature and several bullywugs emerging from the garden.