Groups

you've won a fair bit, considering you have only been on the site for 4 months - I would be satisfied with that ratio :) - you have even been lucky enough to NOT be eligable for the unlucky7 group - so just keep entering giveaways I guess

This is the best group.
Private giveaways > public.

Happens to me sometimes and I'm in much more groups/whitelists than you. Just bad luck. I'm not going to find the groups instead of you though, sorry ¯\_(ツ)_/¯ If you're so eager to win more games, invest some time on it.

I had thought it would be nice if there was a list of groups and requirements, but I'm too lazy to make one.

Looked through a few of the longer threads in the recruitment section instead, and I think there were a few that you would qualify for, Sid.

No, there is no list, as far as I know. You'd have to look aroudn for yourself.
Also, there are plenty of public groups or groups who accept pretty much everybody, but the chances to win, due to the number of members versus the number of giveaways made for that group, are pretty low. There are some exceptions: groups of people who share a common interest, but those are rarely or never publicly advertised here on sg (for example a group of sg people who visit a certain forum or follow a certain obscure indie game, etc), since those are formed by sharing a common interest.
There are also private groups with a decent/high amount of giveaways and a low number of members. Those are sometimes called "trading" groups, since they tend to have an ingroup ratio requirement. Some of those specialize on bundle games (is BundleQuest still alive?), some on expensive newly released ones (ELE I think is the name of one of those), others are a mix of both. The spots also tend to be very limited. Due your current giveaways, you might not even qualify for some of them.
You may wish to join Heretical Giveaways, if you are not part of it yet.