How many letters does the top answer for “frogs, toads, tree toads” have?

The most common answer is batrachia (9 letters).

Crossword clue: frogs, toads, tree toads

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

batrachia 9 letters wn-def

frogs, toads, tree toads

salientia 9 letters wn-def

frogs, toads, tree toads

a larval frog or toad 50% similar → polliwog, pollywog, tadpole

one of the tree frogs. 50% similar → discodactyl

relating to frogs and toads 50% similar → anuran, batrachian, salientian