Well.. it is not that easy.It is my understand of German law that a workers council/union is required at Giga Berlin.
Above 10 workers they have the RIGHT, but not the OBLIGATION to form a workers council. At my last employer we were >200 employees without a workers council.
Additionally workers can join a union, which effectively gives the whole thing more power in negotiations.
If in a sector (e.g. metalworks) enough workers across companies are unionized then this union can also negotiate for everybody in that sector (unionized or not). Basically all metalwork employees against all metalwork employers. This sets standards like minimum wage, maximum hours, etc. pp. in that particular sector.
On the other hand we have the "Vertragsfreiheit" (freedom of contract). So your workers council could argue for more than the minimum - but that is not valid outside of your company
So as an employee you have many rights. But not the obligation to use them. Why would you go on a strike if you are happy, because you are treated good?
Many things are just formalities and only used/enforced in the realm of minimum-wagers or if the expected compensation-rise falls below inflation. If you are decent payed and happy then there is a saying "Wo kein Kläger, da kein Richter" (Where there is no plaintiff, there is no ruling)
And you cannot sue onto behalf of others. Only a person affected by the "bad contract" has a right to sue.
If you as an employer are an ass on a personal basis then employees have several rights to get onto you. Even if they don't win everything is a PITA.
And of course no union would argue for stocks as compensation - but a workers council might
Edit: @FS_FRA beat me to it ..