I have two rear mats in the Mog but they are a bit non-trad.
However..............

My daughter has a black silicon oven mat from John Lewis. I had a look last week, but unfortunately at the moment they are grey, and a tenner each. I'm tempted to try them out, but obviously there's an issue about how long they will last..........
But they are thin and fairly plain and would do the job.
I also have some HD neoprene, but the problem with that is it's 'heavy' and smooth - but I could try that out for nothing as it's in stock.
If you get to John Lewis's kitchen department, have a look - the oven mats are displayed rolled up.