(I hope I got the title correct, still being fairly new to French.)
Duolingo teaches to use être with verbs of motion (https://www.duolingo.com/skill/fr/GS-Past-Tense-2/tips), and the grammar skill related to this does teach several examples, but also one which looks like an exception:
- avoir marché
Are there more verbs of motion that use avoir instead of être?