Upcoming elections

MR/VLD used to be the Liberals and are broadly moderate conservatives. Center right.
PS/SP are broadly socialist, center-ish left, somewhat entrenched in Wallonia.
Ecolo/Groen are left with a focus on environmental matters.
CDH/CDnV are centrists, formally the Catholic party (you have to go back a long way), more recently the PSC (Parti Social-Chrétien)
Liste Destexhe are center-right, vaguely populist, don't like immigrants and seem to think they can successfully out-right-wing the MR.
PP are unashamed populists with no real policies who target morons with some success
Vlaams Belang = Nazis in the wrong colour. Evil scum.
NVA = broadly a right-leaning version of the Scottish Nationalists
DéFi = No, sorry, never managed to work that one out, other than broadly Francophone.
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That's the 11 main ones in a nutshell.

I will develop from what the previous person replied.

DEFI can be described as a slightly similar Francophone version of Vlaams Belang so stay away from it if you are not anti-other people.

Sp.a. is the Flemish version of PS and transport minister Pascal Smet belongs to this party. PS caused big problems during the Canada trade agreement so one should think about that. There are only 17 seats in Brussels capital region and their propaganda is one.brussels this year. They want to unify 19 Brussels commune where you can do your applications etc to one system. They also support bilingual education in Brussels.

PS-PVDA is the workers party of Belgium. They are a unified language party. They have a good selection of young and more mature folks as their representatives.

ECOLO and GROEN collaborated in the last elections but I guess not in this one.

Good luck!

Defi are Francophone, but not really very nationalist as such, and they are definitely NOT far-right neo-nazis like the VB.

Here is another take:

PTB: Stalinists
Groen/Ecolo: far-left, Islam-friendly
CDH/CDV: center-left,
PS: left, in Wallonia more like a Mafia, really
MR/VLD: slighty on the right for money issues, for the rest, left
PP: conservatives, Islam-skeptics
NVA: conservatives, Islam-skeptics
Defi: anti-Flemish party led by a crook
VB: Flemish anti-colonial nationalists

Today somebody described the Green Party as being like a watermelon. Green on the outside, red in the middle. Made me laugh.

Défi (formerly known as Front des Francophones which I am sure you can translate) are very much nationalistic, but I think they are more the equivalent of N-VA than Vlaams Belang, with a narrower focus on Brussels.