Among the first emotions that need mentioning are definitely curiosity (which we feel when someone or something catches our attention and stimulates and pushes us to solve problems and search for answers), happiness, excitement (when our brains are in a state of activeness, but with no determined cause) and even nervousness (feeling scared that we won't manage to deal with an important situation).
While playing games, it’s very likely you’ll also feel: relaxed (low tension and excitement, with no anger, anxiety or fear), confident (when we believe in ourselves and in our abilities), satisfied (when we successfully overcome an obstacle), frustrated (annoyance and agitation when we feel as if we can't overcome an obstacle), angry (an intense feeling of annoyance and displeasure over feeling stuck, or even hatred towards something or someone we perceive as provocative), embarrassed (when we feel as if we've violated a social norm or value, even though it wasn't intentional), and sad (when we feel that we've lost something important to us, like winning the game).
It's important we control our reactions, depending on how well we're doing in the game. It's proven that someone who tries to laugh, despite negative feelings, will process them more easily than someone who lets the negative feelings take over. Healthy competitiveness and cooperation with our co-players are cornerstones for team buildings, which brings about a high level of motivation.
In any case, emotions—both positive and negative—are great for the learning process. Regardless of winning or losing, it's important that the experience taught us something. So next time you experience negative emotions while playing a game, when you feel frustrated, angry or sad, remember that those feelings are also beneficial to your learning process: the stronger the emotions, the more your brain will remember.
Definitions of emotions are summarised from: https://www.psihoterapija-ordinacija.si/osebnost-in-odnosi/slovar-custev.