I only overlimp in protected pots. The pot must either be very multiway or have at least one very loose passive player.

I think it's important not to have a capped range OTB, and I will only do so when others are highly unlikely to bluff

As long as the blinds aren't opening light, I'll limp the button pretty wide if there are limpers infront. Particularly if those limpers play their hands face up post-flop or are just bad.

I'm over limping garbage (this incl small unsuited gappers) only when there are deep fish who can't fold post flop in the pot. 100 BB is meh. Entering a pot with these hands is all about who is in the pot and how deep they are. Once we limp we are resigning ourselves to playing multiway and trying to "make a big hand". This isn't going to happen often so we should be doing it in spots where we can win very big pots. That means there should be deep payoff wizzards in the pot.

I will mix my Axs and Kxs hands between raises and limps OTB for their over flush value.

In general I think the question posed in the OP and many of the responses imply that these spots aren't really being thought about correctly. Our over limping range should be almost entirely dependent on who is in the pot, how deep they are and why the likely result of a raise (playing a larger pf pot with fewer players... Maybe folding out the deep fish) is inferior to playing a smaller multiway pot.

Keep in mind we allow the blinds to play mistake free preflop when we decline to raise. I am not suggesting we should routinely be raising 64o but the likleyhood of players folding has to do with THEIR hand and the size of our raise not with our hand. And The response that suggested raising smaller with speculative hands ensures you will get less folds.

Understanding opponents limp calling ranges is very important also. If there are 4 limpers, a small and BB that's 5.5 BBs in the pot. Why not consider a 12-15 BB raise once in a while in most games it takes it down or gets us heads up with a PP. When it doesn't we can frequently win when v doesn't flop well.

In a nutshell I suggest overlimping with purpose and not just being another passive player in the game who thinks because they are better post flop and have position they can overcome the negative expectation of passively playing junk holdings.