1. Ck2- By far the best paradox game ever made, ever. There have been many games that have tried to blend rpgs and strategy games. But i can't think of one that did it as well as this game. It's only gotten better over time. (For the most part, some changes i do like, like the change to education.) Apart from conclave, being the only bad dlc, ever other one is worth buying. Also they're so many good mods like the warhammer mod or GoT mod that add a lot more replay value to a game with a ton to start with.
2. Victoria 2-This is the second best paradox game, ever. This has the best piece time mechanics in any paradox game. As well as the best economic mechanics. This is probably one of the few paradox games were playing tall isn't only possible but encouraged.
3. Darkest hour/hoi2 I'm putting these two in on number 3 because darkest hour was originally a mod for hoi2. Hoi 2 was my first paradox game and to this day i say it's the best in the hoi series. Period. Kaiserreich for darkest hour is one of the best mods ever, adds so much replay value to such an old game. I just love the all out war of ww2
4. Eu4-One thing i love about this game is that you can take any nation and turn it into a colonial superpower. Everything from a nation in central africa to taking a native American trib into a modern nation and fight back the European scum. A lot of fun and a lot of repaly value. It's only gotten better over time and i love the detection this game is going. Better then eu3 in ever way. (By the way, people complain about monarch points, but honestly diplomats, colonialists and the like are worse. They're either too hard to get early on or useless later on. I feel like people need to take off the nostalgia glass when talking about this game.)
5. Mount and Balde, it's mount and blade. You ride around on a horse, lead a army of dudes around and kill things. Also building your own kingdom is fun too.
6. Stellaris- This game wasn't very good at launch, but after only a few patches and one dlc this game is pretty awesome. I love the detection this game is going, i can only imagine how good it will be a year for now. I'm a space nerd so this is in my ballpark.
7. Magica- Great fun playing with other people, great magic system, funny, just overall good game.
Other games.
Hoi4- This game is meh, it's not bad there's a lot i like about it, it's just really broken atm.
Eu3- Honestly it's not bad, mind you i'm play with the d&t mod. But a lot of the problems people bitch about with eu4 still exist in eu3. Stupid currency mechanics with missionarys, diplomats, ect. Gammy expansion mechanics involving marriages that let you PU anyone you want because they is no relationship limit. Not to say it's bad, just eu4 is better in everyway.