Don't think I've come across a Tamilian yet in M'lore. Not sure if there are many Tamilians here. But lots of Malayalis move here (since Kerala is close by) especially for educational purposes. My Malayali friends love it (they settle here or frequently visit).
Other groups I've come across are Biharis, Punjabis (Sikhs), Gujratis (Well settled) & people from North Eastern states. Closest comparison of M'lore would be Goa so North East people assimilate really well here.
Lots of Gujratis who are born & brought up here. Have 2-3 gujrati friends & they love it too. They have their own community meet-ups where they do Karoke (they seem to enjoy that) & join cycling clubs.
Recent years have seen a lot of Sikhs moving here.
UP/Bihar people are the next, infact came across one today...he was giving me parking directions in Bhojpuri.