Here's a rundown of all the major parties:
Centre Party: A party that got big because they shilled to Russians living here and are now taking a more general approach. Mostly centre-left and have a retarded "gibs me dat" economic policy, only really voted for by Russians and Tallinners. They also have put our government in the red iirc, something no one else has managed to pull off before. Strictly speaking they have ran things smoothly, with our economy still growing and most things going relatively well, but they're still corrupt as fuck, shill to Russians and have increased our taxes and welfare programs to high hell. Something that made lots of people angry was them increasing alcohol tax to Finnish tier prices, nowadays people close to the south would rather just buy alcohol from Latvia and there was a big protest of people going to Latvia to buy alcohol when it first passed. I can attest to this since my family buys alcohol from Latvia and I live close to the border.
They're also corrupt as fuck. They are the most corrupt party in our history, without a doubt.
Reform Party: Former leading party, centre-right and VERY economically liberal. Mostly avoid social issues, popular with business minded people. Sensible economic policy, making things easier for start ups and lowering taxes. Not bad on the economic side, really, but there's corruption issues, they don't care one bit about the environment and it feels as if they will just sell off the country. Most of the country (as in regions) majority support them, including our second largest city. They're basically neck to neck with Centre in terms of votes, but results are in 3 days. No worse than them, but same old shit at the end of the day and their leadership last time was questionable, but they did pull through without completely destroying things.
They also have a massive marketing budget, just like Centre. Marketing budgets really are such a huge influence here, and of course no one will regulate such a thing since both Centre and Reform LIVE off of it.
EKRE (by which I assume you mean the traditional nationalist party): The party for /pol/ and idiots who only care about having sweet nothings whispered in their ear. Popular with Christians and old people. They have grown massively primarily thanks to the migrant crisis, but since the large wave of that is over I think they're decreasing again in popularity.
Retarded economic policy – practically none to speak of in reality. Hey, let's increase our welfare programs and lower taxes at the same time. What could go wrong? Lots could. They don't like talking about economics too often, since they have no fucking clue who they want to pander to. Do we pander to Reform voters who want low taxes and a liberal policy, or do we pander to Centre and left voters who want more welfare and gibs? They promise things too much, they promise things they can't fulfill.
Lots of pandering to fear politics, their ads are just pure fear politics and populism to the max. It's just a rapid fire list of all the bad things that old people don't like and want:
no gay propaganda
<practically non existent, we did pass gay marriage laws long ago and I personally don't give a fuck about it
no migrants and refugees
<even if none of them came here when the crisis was at the peak, and when they did they left quickly to Germany and things have stayed all the same
<even if they have no idea on how they want to do that, and as previously stated their economic policy is pants on head retarded
If I was 20 years older and had dropped 20 IQ points I'd be a EKRE voter. No one who votes EKRE thinks long term, they think on primal urge.
Below this is largely irrelevant. A notable one called Eesti 200 was announced last year in May I think with a manifesto on a popular newspaper. They did everything for attention and flopped hard, policy was generic neoliberal shit
IRL: The former leading conservative right party, who are currently in coalition with I-shit-you-not Centre and the Social Democrats. They compromise too easy and have no spine. Basically equal in terms of votes as SDE, IIRC. Falling off now, EKRE took their spot by being more reactionary.
SDE (Social Democrats): I'm not in the mood for my country and people to commit suicide yet, so no. Again, popular with Russians but not as much as Centre. Usual bullshit of gay rights, minority rights and general faggotry. Basically dying out now, just like IRL. Only popular group they have is teachers.