Yearly thousands upon thousands of animals are rescued, £150,000 was raised over 43 “walkies events” in 2016 and much more.
The problem with this sentence is not the use of "much much more", as a phrase, but the fact that you have a list with 2 items and then are trying to add a third item to the list which means "also there are a lot of other things". No matter what phrasing you use, this will be unclear.
It's not really a list, it's 2 things that you're trying to inflate. Because of this, it's not really clear it's a list, and the "and much more" looks like it applies to one single item in the "list", not the list as a whole.
Also, mixing a general achievement "per year" followed by a specific number for a specific year in the same list makes it confusing to read, and so this makes the "and much more" even less clear.
For these reasons, I have chosen a different phrasing to imply "also, there are other things". Among the ____________ allows you to specific to what you are referring.
The achievements of [the name of the organization] include rescuing thousands of animals each year and sponsoring successful fundraising events to support their efforts. For example, in 2016 over £150,000 was raised in more than forty “Walk [to save the Animals?]" events.
Note how I have split the general and the year specific examples apart too.
