The player-counter plugin currently supports UDP-based query protocols (Source, Minecraft, GoldSource, CitizenFX)
but has no support for games that expose player data via HTTP REST APIs with authentication (that I can tell).

Palworld exposes a rest endpoint with basic auth using the admin password.

Could we add support to look at that data for player count?

For reference, here are the endpoints that are possible:

Server info (name, version, description)

curl -u "admin:{ADMINPASSWORD}" {DOMAIN}/v1/api/info

Metrics (player counts, FPS, uptime, days)

curl -u "admin:{ADMINPASSWORD}" {DOMAIN}/v1/api/metrics

Player list (names, levels, ping, location) - main one for player data

curl -u "admin:{ADMINPASSWORD}" {DOMAIN}/v1/api/players

Sample response
{
"players": [
{
"name": "Name",
"accountName": "Account",
"playerId": "28F2DED7000000000000000000000000",
"userId": "steam_1234",
"ip": "",
"ping": 59,
"location_x": -3113.724609375,
"location_y": 122099.359375,
"level": 51
}
]
}