"except rarely" is a perfectly correct phrase for use in written English.
You can use the phrase to describe a situation where something usually happens, except for very infrequent exceptions. For example: The store is open every day of the week, except rarely when there is a holiday.
("Don't worry," she said. "I don't talk on it except very rarely").
But the punk stance – that everyone else deals in bullshit except yourself – rarely stands up to scrutiny.
In Bhutan, large predators, except leopards, rarely come to the human settlements to take away livestock.
Except, I rarely completely forget in-development Broadway musicals.
He's playing the ostensible hero of the piece, flashy Formula One driver James Hunt, except he rarely acts heroic, and often comes across as a straight-up jerk.
Though the underhand serve is not used in professional or any competitive tennis play (except very rarely when your opponent is tired or feeling sneaky), this is a great serve to use for beginners and children because it's easier to get the ball to clear the next and to land in the service box and to begin play.
Beyond the gay community, progressive religious heroes — MLK excepted, of course — rarely get the recognition they deserve.
All viridans streptococci (with the exception of S. thermophilus, which is not associated with humans) are commensals of the human upper respiratory tract and, excepting S. pneumoniae, rarely cause disease in immune-competent individuals.
Collectors of famous Bordeaux wines, except some Americans, rarely worry about the blend or the appellation; they buy on the strength of the vineyard's reputation and the vintage year.
However, the protein fails to form rings in the ΔminJ strain except at the rarely formed septa.
