Hoard of treasure initially found on ramble (5)
I believe the answer is:
trove
'hoard' is the definition.
(I've seen this before)
'treasure initially found on ramble' is the wordplay.
'initially' indicates taking the first letters.
'found on' is a charade indicator (letters next to each other).
'ramble' becomes 'rove' ('rove' can be a synonym of 'ramble').
The first letter of 'treasure' is 't'.
't'+'rove'='TROVE'
'of' acts as a link.
(Other definitions for trove that I've seen before include "Collection of treasures" , "box of delights?" , "Treasure of unknown ownership" , "Store of treasures" , "hidden valuables" .)