1st is Able Sisters from Animal Crossing, the 5th is Floss from Fortnite, 7th is from 3D World, 9th is an extract from the Silent Hill 2 Theme, 11th is The Avengers Theme, the last one is the Imperial March from the Original Trilogy (Star Wars)
The second one is Gourmet Race, the third is Freddy's Theme from FNAF, the fourth is the Tetris Theme, the 6th is Fallen Down from Undertale, the 7th is from a Mario game but I forgot which, the 8th is the Game Theory theme, the tenth is Minecraft Sweden, the 12th is He's a Pirate from Pirates of the Caribbean, the 13th is Blue Bird from Naruto. Not sure about the others.