INTPs I know: major hobbyists, they will try anything. And if it's for work they'll master it and work pretty intensely. Can be a bit oblivious socially but they mean really well. (typical nerd in movies, a little less exaggerated).
ISFPs I know: Keyword: Playful. Feels "warm" to others when they're happy. Look very calm, composed. Secretly exceptionally chaotic and potentially messiest MBTI type. Focuses on a handful of interests at a time. Has unexplainable gut feelings about the future. Tendency to feel "trapped". Hard to connect with unless they specifically like you.
INFPs I know: Less messy than ISFPs, much more tendency to over think and on the opposite side are less likely to feel trapped in environments. More likely to go with things as they are. Needs pushing to get out of bad situations. Can struggle to know when talking Ne is appropriate (ie. Around sensors haha). Look self conscious in their own bodies. Fussy about their literature and music.