Here are some Sonic noisemakers for the party. These are rollout/blowers (usually makes a whistle or tweet sound) The springy yellow paper at the end unrolls. The Sonic theme here is added by the cardboard disk with Sonic art on it that fits over the plastic tube part of the…
This keychain isn't officially Sonic, but it was a part of a Sonic promotion when the Sega Dreamcast came out. You can sort of see the reddish/orange-ish swirl on it.