Here is my list of Welsh vocabulary relating to elections.
It can be downloaded from the Download Documents page.

Etholiadau / Elections

Aelod Cynulliad AC	Welsh Assembly Member AM
Aelod o Senedd Ewrop ASE	MEP
Aelod Seneddol AS	MP
Annibynnol	Independent
Ardal etholiadol	Electoral division
Bwrw eich pleidlais	Cast your vote
Cerdyn pleidleisio	Poll card
Cerdyn pleidlais bost	Postal poll card
Cynghorwr	Councillor
Cyngor	Council
Cywirdeb gwleidyddol	Political correctness
Darllediad gwleidyddol plaid	Party political broadcast
Diwrnod pleidleisio	Polling day
Ethol	To elect
Ethol Aelod Seneddol	Election of Member of Parliament
Etholaeth(au) eb	Constituency/ward/electorate
Etholiad Cyffredinol	General election
Etholiadau llywodraeth leol	Local government elections
Etholwr	Voter
Gorsaf bleidleisio	Polling station
Gwasanaethau Etholiadol	Electoral Services
Gwleidydd(ion)	Politician(s)
Gwleidyddiaeth eb	Politics
Gwleidyddol	Political
Isetholiad(au)	By-election(s)
Llywodraeth Cymru	Welsh Government
Llywodraeth leol	Local government
Llywodraeth(au) eb	Government(s)
Papur pleidleisio	Ballot paper
Plaid Cymru	Party  of Wales
Plaid(iau) eb	Party(ies)
Pleidlais bost	Postal vote
Pleidlais eb	Vote
Pleidleisio	To vote
Pleidleisiwr	Voter
Prif Weinidog	Prime Minister
Prif Weinidog Cymru	First Minister
Swyddog Canlyniadau	Returning Officer
Twyll etholiadol	Electoral fraud
Y Blaid Geidwadol	Conservative Party
Y Blaid Lafur	Labour Party
Y Blaid Werdd	Green Party
Y Comisiwn Etholiadol	The Electoral Commission
Y Democratiaid Rhyddfrydol Cymru	Welsh Liberal Democrats
Ymgeisydd (Ymgeiswyr)	Candidate (Candidates)

Mae’n bwysig bod pawb yn bwrw pleidlais / It’s important that everyone votes