Ciro Santilli With Telescopes however, it is possible. www.quora.com/Can-we-distinguish-individual-stars-in-other-galaxies-or-would-it-be-equivalent-to-say-we-know-there-are-other-forests-of-stars-galaxies-but-we-cant-tell-the-individual-trees-stars-What-is-the-farthest-individual/answer/Jerzy-Micha%C5%82-Pawlak contains an amazing answer that mentions two special cases of the furthest ones:
- gravitational lensing observation
- a star that is far but visible because its light is reflected by a nearby nebulae
But what we can definitely see are globular clusters of galaxies. E.g. the article en.wikipedia.org/wiki/Messier_87 basically gauges the size of galaxies by the number of globular clusters that they contain.
We can't see individual stars outside of the Milky Way:Any single star outside of the Milky Way cannot be seen.
The Large Magellanic Cloud stands out as the brightest thing we can see from outside the Milky Way by far!
Some stars are so close that we can actually see their angles move with time due to the relative motion between them and the Sun, e.g. Proxima Centauri!