Here are some useful websites for Welsh learner resources/games and activities:
Astro Antics
http://www.bbc.co.uk/wales/learning/astroantics/
Zoom through space to find stories, songs and games for young Welsh learners aged 5-7.
Penigamp
http://www.bbc.co.uk/wales/learning/penigamp/
Eight engaginng, interactive games and activities which have been compiled for KS2 learners of Welsh.
BBC Teach YouTube
These clips are suitable for teaching Welsh to 5-11 year olds. They encourage children to use Welsh incidentally outside in the classroom in everyday situations.
Ciwb
An online magazine for Welsh learners in Years 7-9 but also useful for upper Primary school ages.