Recent papers have reported 104 M☉ BH in the massive globular cluster G1 in M31 (Andromeda). There is also a report of a 3000 M☉ BH in M15.
There are also indications of intermediate black holes from X-ray observations. If this is true then it would open up a whole new range of science for LISA, with a likely high rate of capture of intermediate BHs by supermassive BHs in galactic nuclei. It would also allow precision test of general relativity with high SNR events. However it is not clear that the recent reports of BHs in globular clusters are definitive and these results are strongly disputed.
References:
van der Marel et al. (2002) Astronomical J, 124, 3255
Gerssen et al. (2002) Astronomical J. 124, 3270
Gebhardt et al. (2002), ApJ, 578, L41