For me: whoBird (F-droid) and iNaturalist (Play Store)

whoBird listens to ambient bird sounds and tries to identify them. The database for the area you are visiting needs to be downloaded beforehand. If there is a match, it shows the name and a photo.

I love documenting the wildlife i see when i travel, and i try to record every plant, animal(including bugs and birds, and fungi) i encounter so that i can keep a record of where, when, and how many times i've seen each species.

iNaturalist is a volunteer/community science database documenting wildlife around the world. They have an Android app that lets you upload geotagged and/or timestamped photos of wildlife, and they are added to a database available for free to researchers.

I use whobird to try to spot birds when i hear them hiking or walking, take a photo, then upload it to iNaturalist to keep track. It's the most fun part of travel to me.

I looked over my phone and that was the only "travel app" i have from F-droid. Most of the ones i have are everyday apps that i use travelling or not.