HOI4 is one of my favorite games and one I have played the most.
Hearts of Iron IV (4 in latin) is a grand strategy game made by Paradox Development Studios. Its set in the year 1936 and you can choose a country that you wish to play as from that time period, you can choose our to manage their economys, diplomacy and wage wars against other nations. It also has a large modding community if you ever get dissatisfied with just playing in the WW2 era, theres plenty of mods, such as a mod that lets you play in a WW1 scernaio, and a lot of "what if?" mods exist, such as what if germany won WW1? or what if germany won WW2?. In all its one of my favorite games because I'm a big strategy fan and if you also enjoy strategy game this is a definite must buy.
SCP:Secret Labratory isn't as popular as a game but its still one of my favorites due to how unique it is.
SCP Secret Labratory is a very fun and unique game, where you are spawned in as one of three factions, the Foundation Team (Guards, Mtfs, and Scientists) or the Insugency Team (Class D, Chaos Insurgents), and finally SCPS. At the start of a match you spawn in as either a Guard, Class-D, Scientist or SCP. As a Class-D or Scientist you must find a card to either upgrade at 914 or find one around the zone to exit the zone you are in and escape the facility, theres 4 zones, Light, where Class-D and Scientists Spawn, Heavy, where SCPS spawn, Entrance, where Guards Spawn and surface where Class-D and Scientists must reach in order to escape the facility and join either the ranks of the MTF (Scientsts) or Chaos Insurgents (Class-D) However if a Scientist is detined by a chaos and escape they become a chaos and if a Class-D is detained and escaped they become an MTF. Guards spawn in Entrance and are given a gun and a card, their main goal is to kill the SCPS and let Scientsts escape, also Class-D if they want but they can also just kill them. There are 6 SCPS in the game, 173, 079, 096, 049, 106, and 939, it would take way too long to go over each one so I'll let you experince them yourself in game. SCPS goals are to kill everybody in the facility and then they win. MTF and Chaos can spawn every 5 minutes and thats when all the dead people (spectators) join in on the match, MTF have to kill all SCPS and Chaos while Chaos have to kill all MTF's and SCPS. Chaos's goals are to get Class-D's to escape so they can get more tickets and MTF have to get Scientists to escape for more tickets (tickets are how the game decides who spawns in every 5 minutes) In conclusion SCP:SL is a very fun game that I love to play, its a bit competitive though nowadays but if you find the right server of people I'm sure you will have a blast.
Heres a Preview of the game on steam (its free by the way). 😁