The following link will let you sign up to BalliolTOOT, only works for the first 25 users so be quick :)).
https://toot.ballioljcr.org/invite/tKgZME2q

Finally to get you started here is Greta Thunberg's account https://toot.ballioljcr.org/@gretathunberg@mastodon.nu

and Stephen Fry's
https://toot.ballioljcr.org/@stephenfry@mastodonapp.uk

I will be accepting custom Emoji submissions later in the week. ❤️