This happens a lot of the times when playing live no matter what stakes, regs, rec, fish and whales are all guilty of this according to my opinion.

Pre-flop, when there is an initial raiser and cold call from anyone and then a 3-bet and the cold caller calls the 3-bet. Is this a sign of hand class that requires a lot of implied odds as they need to hit in order to make money. Therefore, a lot of the middle portion of cold callers perceived range would be calling an open then over calling a 3-bet. I assume this would be a lot of suit broadway combos and pocket pairs.

Any comment on the what the range of a call to an open and over call to 3-bet as well would look like?

Pocket 88

At low stakes, all this signifies is that it is a hand the player wants to see a flop with. While regulars will have heard of implied odds, most of them don't know how to calculate it. Sure, it is include pocket pairs and broadways, but also will include suit connectors.

This is extremely V dependent. I think PPs are the hand class that is in basically everyone’s range (depending on sizing). But old men especially mightve cold called with very strong hands like TT-QQ AK and obviously will also cold call the 3 bet. Other Vs will just call with their whole range, ESPECIALLY if the PFR called the 3!

Just like everything else in poker it depends. It's gonna be a lot of PP's but it could also be hands like AQs, AK, T9s, 56s, KQs, TJ, or even 57s type hands. It really depends on the player, the original raiser's range, and the number of callers before the cold caller called. There's an older guy in my player pool who has 3 or 4 different birthdays of his grand children and he'll play them pre no matter what.

Absent specific reads on a particular V, when someone double flats pre, it usually means their hand looks too good to fold but wasn't strong enough to 3B themselves.

This range is comprised of the less sexy suited aces, from A9s down to A2s, all the also-ran Broadway combos like AJo, KQo, KTs, QJs, all the pairs from 22 up to 88, all the suited connectors from 43s up to QJs, a lot of the middling to upper suited 1 gappers, and the higher 2 & 3 gappers like K9s and Q8s.

On paper, all these hands look playable - small to middling pairs that can flop sets, hands that can make nut flushes, hands that cal make a straight or flop a good combo draw, etc. Their defining characteristic is that they don't have much if any showdown value, yet have potential to improve, often in sneaky ways that can cooler an opponent.

If you look at that range, it's pretty big, but we can think of it as "collapsed" because of what it does NOT include. It doesn't include hands that were clearly strong enough to raise, or hands that are clearly garbage and should be insta-folded.

That said, some players simply don't have a 3B range beyond AA/KK or AK. So you will sometimes see someone double-flat with some pocket pairs or other hands that were strong enough to 3B, like TT-QQ, AQs and KQs.

Some other players simply don't have much of a fold button, so the range can include 32, KTo, J6s, and all sorts of other unplayable trash.