It partly depends, as it always does, no your definition (of 'extragalactic star#), but there are a very great many that have been observed.
Leaving aside stars in globular clusters (they aren't 'galaxies', but I somehow feel they don't qualify, under whatever definition wolfram ends up using), there are all those in the various streams which researchers using SDSS data have found - those stripped from globular clusters and satellite galaxies, the streams which appear to have no parents, and the thousands of just plain old stars that are out there, beyond the usual boundary of the Milky Way.
Then there are the thousands in the Virgo cluster ... IIRC, the first of these was discovered a decade or more ago, and recently the HST imaged a small region, discovering lots more.
There was also, recently, a deep image of the Virgo core, showing streams and the faint glow of lots and lots of 'extragalactic stars'.
Some researchers have tried to use 'field' planetary nebulae, as tracers of the outer reaches of some galaxies, to better estimate the distribution of DM (wolfram may not count these as 'extragalactic').
Finally, in almost any image of interacting galaxies, esp those with nice long 'tidal tails', there are great numbers of stars that are well on their way to becoming 'extragalactic'!
