Unfortunately, there is currently an utter and complete lack of support for Supports.
They used to create a new Support whenever they released a new character. They no longer do this. Kraven, Namor, Prowler, 5Loki, 5 Doom, Kitty, Shuri and BP all got them, but they didn’t create any new Supports for any of the most recent releases, meaning Hammond, Spider Miguel, Capt Worthy, Juggernaut, or Wolfsbane.
In addition, they’ve simply stopped providing any means whatsoever to get Advanced or Master Support tokens. At all. You can get Beginner tokens in event vaults and rarely in a Heroes for Hire pack. But not in the Taco vault, not by character progression rewards, not in SHIELD resupply, not in VIP rewards, and not in event progression. And you cannot buy any level of Support token with any other in- or out-of-game currency. Meaning you can’t use HP, CP, ISO, Red-ISO or even good ol’ cash to buy them.
Beginner tokens have a 1:50 chance of pulling a 4* Support card. But only from a limited list of 15 Supports. Want a Flerken or Pizza Dog? Nope, not currently available in the Beginner Token pulls. My understanding is that they rotate those, but I do not know when or how often.
Oh, and you can’t currently get a 5Support power at all (to clarify, I’m referring to the 5th level of power of a Support, not a Support for a 5 character.) Those are only available from an Advanced or Master Token which you can’t get.
So, abandon all hope, ye who enter into the Support chase. Be happy to get the occasional Beginner token, use all of your Red ISO to level up the Supports that you can use effectively, and focus on other parts of the game.