I'm pretty sure I'm a ISFP 5w4. I relate most to the Basic Fears and Desires of type 5 (competence issues), which I believe is the most important part of enneagram identification. Type 5 tends to be associated with NT-like knowledge accumulation, but that accumulation doesn't have to be so bookish. It can be about perfecting a performance or skill. The main thing is the fear of being worthless and the need to master some sort of skill in order to feel secure.
As a ISFP 5w4 (assuming I'm correct about my self-typing), I feel I can understand intuitive concepts fairly well and I'm pretty good coming up with interesting points of views (more interesting than most intuitives' ideas imo

Literally no one understands what the fuck I'm talking about though when I try to explain them though

) I have a very surreal imagination. I relate a lot to the musician Tom Waits (ISFP possibly). I worry a lot about how incompetent I am. I have a hard time conforming to the norms. I have a subconscious urge to do things differently just because (w4 influence). Pretty good with working with my hands. I'm a musician and like to write, and I'd say I'm pretty good at both of them (i hope

). Extremely critical of myself, therefor of others as well but I try to curb it. Generally quiet but I can be a decent conversationalist when I want to be. Philosophically I'm as nihilistic as they come, though I probably don't come across that way. The one philosopher I've been able to actually read and understand somewhat is David Hume, and I agree with a lot he has to say. I gravitate towards anti-philosophy philosophy (zen buddism, scepticism). I don't really talk about that kind of stuff with people because, or anything that """""deep""""" for that matter, because I don't have any strong opinions on those kinds of subjects. I know Fi is generally associated with morality or emotions, but I think of it more as the ability to recognize harmony (maybe beauty as well when linked with Se???).
Other than that I'm probably just like any other ISFP. I'm mellow, easy-going, quiet, focused on whatever I'm doing, like nature, serious, like to play music, avoid conflicts, spontaneous, bit of a chameleon, etc, etc...