Singleplayer:
1. Create a team, example:

/team add Hi

2. Join the team:

/team join Hi

3. Go into Spectator mode

/gamemode spectator

4. Press any number to open menu
5. Press "2" (to open "Teleport to team member"
6. Select your own name (Press "1")

Bugs

1. You shouldn't be able to teleport to yourself (that's why you can't use "Teleport to player" when you are the only player in the world)
2. The menu should close after teleporting (what it doesn't do right now, it stays open with no option exept "9" (Close))