Looking at election to the football league, here's a list of Welsh sides who failed in their bids to join.

1921 - Abertillery Town, Barry, Bridgend Town, Pontypridd, Aberaman Athletic (who later joined/split/joined/split etc with Aberdare)
1922&3 - Pontypridd, Llanelly
1925 - Mid Rhondda (?)
1927 - Aberdare
1931 - Merthyr, Newport
1932&3 - Merthyr, Llanelly
1947 - Merthyr, Llanelly, Barry Town, Bangor City
1948 - Merthyr, Bridgend
1949&50 - Merthyr
1951 - Merthyr, Llanelly
1952&4 - Merthyr