Let's, well, firstly skip Turisas because I will be crazy whenever I come to them.
But still, a good beginning would be Wanaja Festival. I went there mainly for Turisas but then I knew many great musicians during the whole festival.
(1) Jenni Vartiainen is a very different one. Although not as famous as Tarja Turunen the ex-vocal from Nightwish, her beautiful voice comforts me and featured dance (mainly on videos) is impressed. When I was in Wanaja Festival and listening and watching her show, the wind blew the tree beside the stage, and immediately lots of leaves falling flying in the air. It was an amazing picture, just like those leaves were dancing and that completed the whole show. Definitely a magical atmosphere.
(2) Yö--I knew this band when I was checking the band list of Wanaja Festival. It is followed by Turisas. It is not difficult to find some of their songs on Youtube, but not until the festival did I realise how charming they are. Also, I reckon those Finns shared the same idea as me since they started to find the best position much earlier than the beginning of the show. It was absolutely great, and after I came back to the UK I fell in love with their 'Rakkaus on Lumivalkoinen', also the English version Love me like you never did before sang by Jukka Lewis. So here it is, enjoy.
(3) Týr--this band did not have a gig in Wanaja Festival. But it is still famous when people search 'viking metal' or 'Finnish metal' on the internet. They are not from Finland actually, but Færøerne in Danish. Sometimes they write songs in English, sometimes might be Danish or Faroese. I have no knowledge of the both. However, it is still very nice to enjoy their high quality music. I do not really have any favorite song of Týr, but they are averagely good.