The enemy of my enemy - my friend

[cuprum]

 Learned today previously unknown to me fact.

 May 10 and June 14, 1918 Red Guards-border guards and British Marines were allies. Together they engaged in battle with the Finnish rangers which invaded to the Russian territory ...
This clash can serve interesting and unusual scenario to skirmish ...

 I know that there was an episode when the Bolsheviks and Lithuanians acted as allies against the Poles.

 Red participated in fighting against the Turks in alliance with the British, Armenian nationalists and white in the battles for Baku ...

 Detachments of of anarchists many times entered into an alliance with the Bolsheviks.

In 1918, the battalion Ufa Directory  fought against Bolsheviks ... under red banners.

 And there any other known facts unusual alliances in this period?

[commissarmoody]

Civil wars and revaluations historically have many marriages of convenience. 

[TheBlackCrane]

And there any other known facts unusual alliances in this period?

I think the Baltic and Finnish civil wars/liberation wars probably had a fair few such combinations. If I recall correctly a German force in Latvia actually ended up being the 'West Russian Army' in a three-way fight between the Bolshevik Russians and Latvians and the National/"White" Latvians who were supported by the Entente.

Though I am sure there are others on here who have a more in-depth knowledge than I 

[Mark Plant]

I think the Baltic and Finnish civil wars/liberation wars probably had a fair few such combinations. If I recall correctly a German force in Latvia actually ended up being the 'West Russian Army' in a three-way fight between the Bolshevik Russians and Latvians and the National/"White" Latvians who were supported by the Entente.

There was indeed a "West Russian" Army that was largely German, although with a White Russian element. However that was a front for the Freikorps, rather than an actual alliance. The Latvians faced them and the Moscow Bolsheviks, but quite separately, and the Soviet front was very quiet at the time. (Oddly, the Latvian army facing the Reds at the peak of their battles against the German Freikorps was the Baltic German Landwehr.)

The Estonians actively fought Bolsheviks and Freikorps at the same time, which is a better example of a three-way conflict, made all the more confusing by Iudenich's White Russian army adding a fourth element. The Estonian Army also contained a Latvian element, but relations with Latvia were mostly quite strained, and an ethnic German unit, just for good measure.

(The Lithuanians simultaneously fought Bolsheviks and Freikorps, though describing that conflict as "hard to find information about" is a gross understatement.)

However the most confused conflict, by quite a long way, was the Ukraine. It takes quite a lot of reading to get even a small grip on that conflict. It had Ukrainian Nationalists (three varieties), Reds, Whites, Cossacks, French (and Greeks), Greens, Poles and Romanians. And I make it at minimum a five-way conflict in the west Ukraine (and by "sides" I mean groups that fought all the other five -- its more if you count partial conflicts).

Some couldn't even work out which side they were on -- Makhno fought with, against, with and against the Bolsheviks. The West Ukrainians briefly fought with the Bolsheviks too.

[Plynkes]

And there any other known facts unusual alliances in this period?

I seem to remember the opposite of an unusual alliance happening too, with the German and Ottoman allies briefly falling out and coming to blows in the Caucacus.

[Mark Plant]

I seem to remember the opposite of an unusual alliance happening too, with the German and Ottoman allies briefly falling out and coming to blows in the Caucacus.

I don't recall them actually fighting.

Given that Denikin lead a coup to take over his Don Cossack "allies"; and the numerous rebellions on the Bolshevik side that were put down with bloody force (Grigoriev, Kronstadt) it was just a lover's tiff.

[Red Orc]

...
Some couldn't even work out which side they were on -- Makhno fought with, against, with and against the Bolsheviks. The West Ukrainians briefly fought with the Bolsheviks too.

Isn't that rather that the Bolsheviks allied with the Makhnovists, then fought them, then allied with them, then fought them again? My understanding (perhaps derived from anarchist sources?) is that it was Trotsky who twice broke the alliance.

[cuprum]

I would not be so categorical 
Makhno too not always adhered to the agreements.

[Red Orc]

Fair enough. I haven't researched the topic in any depth and am perhaps over-reliant on the Makhnovists' own accounts.

[cuprum]

Of course. Each party to the conflict was pursuing its own goals.
Makhno had left orientation. Therefore, he often went to the alliance with the Bolsheviks, because they had a common enemies.
But any State Makhno regarded an enemy - and the Bolshevik dictatorship deny too ...