Heffalump trap:

https://lichess.org/api/games/user/{player}?clocks=true&perfType=rapid&max=200

Classical games:

https://lichess.org/api/games/user/{player}?clocks=true&perfType=classical&max=30

Games from a player with options:

lichess.org/api/games/user/{player}?clocks=true
lichess.org/api/games/user/{player}?clocks=true&perfType=rapid
lichess.org/api/games/user/{player}?clocks=true&perfType=classical&max=6

Games from a Swiss tournament:
lichess.org/api/swiss/{tournID}/games e.g. https://lichess.org/api/swiss/69wSfABK/games?clocks=true