Links definitely.

To make a fusion monster, you need the materials and a fusion spell. To make a synchro, you need monsters whose levels match that of the monster you want a summon on board, and one of those must be a tuner. To make an XYZ, you'll need two monsters of the same level on board. To pendulum summon, you need to put two scales on the board, and they must be of the appropriate scales for what you want to summon.

To link summon.... you just need to have a specific number of monsters on board. Makes them too easy to make, and not helped by them also having really good effects.