Fulham FC Women said the club was “shocked and saddened” and its thoughts were with Amelia’s family and friends.
Oxford United said it was offering support to Amelia’s family, players, coaches and staff “impacted by this tragic event”.
Kidlington Football Club was among those who have posted messages, it said: “Everybody at Kidlington Football Club sends our sincere condolences to Amelia’s family and to everyone at Oxford United FC at this incredibly sad time.”
Didcot Town Football Club added: “The thoughts of everyone at Didcot Town and Didcot Town Youth are with the family and friends of Amelia and Oxford United.”
A post from Oxford City Football Club said: “All of us at Oxford City send our sincere condolences to Amelia’s family and everyone at Oxford United at this incredibly sad time.”
Thames Valley Police said Amelia was taken to hospital after she collapsed but died later on Saturday evening.
The force said: “There are no suspicious circumstances and this is now a matter for the coroner.
“Our thoughts are with her family and friends at this most difficult time.”