There is the ECAA and the ENGAA; they are the Cambridge economics and engineering entrance papers respectively. Unfortunately they don't have worked solutions like TMUA, but there are solutions. However, they are in my opinion quite a bit easier than TMUA (If TMUA were a 10 in difficulty, I'd say they're about a 7, but of course this is just opinion). I'd personally recommend you start on these papers before you go through the TMUA, but of course the earlier you practice the better. The NSAA or natural science admissions test also contains maths questions similar in style to TMUA, but I'm pretty sure they are the same as the ones in ECAA or ENGAA.
The best resource apart from TMUA past papers is the
MAT, or the Oxford admissions test for Maths / CS. It differs in that it has both multiple choice and long answer questions which are for specific subjects. Whilst these longer questions may not necessarily be useful for TMUA, I'd recommend doing them anyways, even for subjects you are not applying for as they are quite similar to interview questions you may get.
If you run out of MAT papers, there are pre-2007 papers
in this link. Unfortunately, there are no solutions, but there may be some threads covering them.
A final thing, I'm pretty sure the MAT is one day before the TMUA. You might want to sit the MAT too even if none of your unis need it, as you technically get one more past paper to practice in exam conditions; but the stress of sitting another paper may be a hindrance, not a benefit, and there is probably not much improvement that could happen one day before your exam, so decide if you want to do that.