In the most recent Tiny Rebel Games newsletter is a reveal of three new characters coming to the game to coincide with the 500th issue of Doctor Who Magazine. Two of these I was aware of, the third is Shayde (pictured left in The Stockbridge Horror comic strip).
The other two characters coming with Shayde are Abslom Daak and Frobisher. The three characters will be available via a code to be published in the special 500th issue of Doctor Who Magazine. No information as to how else they might be available, my assumption is a wait of a least a few months. My main concern is saving enough Trickster fragments to boost some of these once available. No news on colours / abilities, my thought is it would be great if Daak had a special anti-Dalek ability! I guess Frobisher will be a colour changer, as to Shayde list of powers in the TARDIS wikia link above is large, so no idea!
There will also be a fan Sarah Jane coming soon as well. All jolly fun, but bring me Jamie, Zoe and more classic companions, please!