There are, but you often run into limitations in praxis. For example you can take a look at tokio::LocalSet::{block_on,run_until} which require neither 'static

There are, but you often run into limitations in praxis. For example you can take a look at tokio::LocalSet::{block_on,run_until} which require neither 'static nor Send or Sync. But then spawn_local does require 'static. Same is true for smol where we have smol::block_on, smol::{Executor,LocalExecutor}::run and here too we have the limitation that calling spawn on a LocalExecutor requires static.