I will just give the partial answer for denmark, and thus mostly pro-union laws.
- Trade union fees are tax exempt.
- Unions are given the administration of some unemployment benefits, meaning they can use that to build a big organisation. (this is a little more complex)
- There is no minimum wage. (note 1)
- There is a special court for union disputes with managers.
- There are rules that enforce different kinds of collective representation.
- Worker-elected representatives are harder to fire.
- The right to strike is in the law.
And then the one rule that is anti-union.
- Managers have the right to lead workers. (note 2)
Here is a good wiki reference about the general idea for Denmark:
Note 1: The minimum wage seen from a Scandinavian perspective is the last resort to implement when trade unions loose power. E.g. in Germany the minimum wage was not introduced until 2015 and it was the biggest trade union Ver.di that accepted it had to be implemented because trade unions had lost a lot of power.
The general problem for the trade union is that e.g. if a café is blocked that pay minimum wage then that is per definition legal, where-as when there is no minimum wage then workers will more often get a trade union specific salary. E.g. Taxi drivers can negotiate a salary for Taxi drivers etc.
Note 2: To understand the September Compromise that forms Denmark then it is important to know that in 1899 there was a strike where all workers in the cities were on strike, and farmers where driving food to the cities to support the workers. Inspired by communism the workers wanted a society where leaders did not manage, but the Agreement established that managers could lead the workers.