In EQG Rainbow Rocks Derpy tries to pick a fight with Bulk Biceps.

In the fight against Tirek she was with the pegasi attempting to attack him head on.

In Putting Your Hoof Down she continues laughing after Iron Will stares down the crowd.

In her single speaking role Derpy destroys the town hall without paying too much attention to what she's doing.

She's fearless, apparently strong given that two pegasi can somehow carry a wagon, piano, anvil, and flower pot by themselves, and is always there to help. Literally, she seems to be wherever the mane 6 need to go, no matter how difficult it would be to get there.

In the stories we write about her, she's a pretty good mom too. Dinky is in good hooves.