Here ya go:
A fool gives full vent to his anger, but a wise man keeps himself under control (Pr. 29:11).
A gentle answer turns away wrath, but a harsh word stirs up anger (Pr. 15:1).
When a man's ways are pleasing to the Lord, he makes even his enemies live at peace with him (Pr. 16:7).
Don't have anything to do with foolish and stupid arguments, because you know they produce quarrels. And the Lord's servant must not quarrel; instead, he must be kind to everyone, able to teach, not resentful (2 Tim. 2:23-24).
All of you, live in harmony with one another; be sympathetic, love as brothers, be compassionate and humble (1 Pet. 3:6).
Do not let any unwholesome talk come out of your mouths, but only what is helpful for building others up according to their needs, that it may benefit those who listen (Eph. 4:31).
Get rid of all bitterness, rage and anger; brawling and slander, along with every form of malice (Eph. 4:31).
If you are wise, your wisdom will reward you; if you are a mocker, you alone will suffer (Pr. 9:12).
An unfriendly man pursues selfish ends; he defies all sound judgment (Pr. 18:1).
He who guards his lips guards his soul, but he who speaks rashly will come to ruin (Pr. 13:3).
Be kind and compassionate to one another, forgiving each other, just as in Christ God forgave you (Eph. 4:32).
As God's chosen people, holy and dearly loved, clothe yourselves with compassion, kindness, humility, gentleness and patience (Cor. 3:12).
Here's some really good ones:
A fool shows his annoyance at once, but a prudent man overlooks an insult (Pr. 12:16).
Do not repay anyone evil for evil. Be careful to do what is right in the eyes of everybody. If it is possible, as far as it depends on you, live at peace with everyone (Rom. 12:17-18).
Do not repay even with evil or insult with insult, but with blessing, because to this you were called so that you may inherit a blessing (1 Pet. 3:9).
There's lots more verses like this, but this should be enough.