This is the 346th most frequent Slovak word.
všetkým
"Všetkým" means "to everyone" or "to all" in English.
In this sentence, 'všetkým' is also in the dative case, indicating the group (us all) that the liking (a reflexive experience) pertains to.
Všetkým sa nám to páčilo.
We all liked it.
Here, 'všetkým' is in the dative again as the indirect object who received the help.
Pomohol im všetkým úspešne dokončiť úlohu.
He helped all of them successfully finish the task.
The word 'všetkým' here is used in the dative case as it is the indirect object of the verb 'prajem' (I wish).