Tony: He gets jealous fast. So when he does get jealous, he will hold you really close to him and kiss you everywhere. He would also try to butt-in into the conversation just to make the other guy uncomfortable and eventually leave.
Steve: He would have an internal battle of what to do but he'll just end up intertwining your fingers and staring the other guy down. This is really effective thanks to his height, so he seems to be towering over the other guy.
Thor: He holds Mjolnir and wraps an arm around you. He gives you as many forehead and cheek kisses until the guy eventually leaves.
Bruce: You both wrap your arms around each other and he gives death glares at the other guy. He tries his best to keep the Other Guy at bay too.
Clint: Clint rarely gets jealous and when he does, hes very chill about it. He just stays beside you, not doing anything. After the guys leaves, he'll roll his eyes and joke about how he needs to create a disguise for you(just so you could stop attracting others). And then he'll give you a kiss on the forehead.
Bucky: He is very protective. He would pull you close to his side and trace patterns at your hip. He would also clear his throat and butt in to the conversation. And eventually tries to pull you away from the other guy.
Pietro: He is impulsive and impatient. He will put an arm around you and fidget around. Pietro will try to end the conversation quickly and bring both of you to a different spot really fast.