You can also parry with two-handed weapons (including dual wielded weapons like flesh rippers and dual knives, and even the spellcasting staves), but they are very ineffective in blocking attacks without parrying. One-handed weapons tend to have poor overall blocking characteristics, always wield some type of shield with them. With big enough stagger limit you will be able to parry and stagger ever stronger opponents, even if you take a bit more damage than you would with the block/parry armor provided with shields.

Another thing of note is how the game displays your skill-adjusted values with a given weapon or shield. An adjusted value's number and range is displayed in yellow inside brackets.

For weapons, the base damage value listed in weapon description and stats is the upper limit of damage. But for blocking it's the actual base value, or lower limit, and the adjusted value is higher since it's increased by your blocking skill. You can check the Fandom wiki for full block ranges since they are not displayed in game until your blocking skill is maxed out.

The wiki also has a convenient list of shields[valheim.fandom.com] to see which ones are roundshields (or regular shields), and which ones are bucklers or tower shields. Might be useful especially if you play the game in different languages. Might be that the naming conventions are not as clear in every language.

You will also need to learn what kind of blocks, and shields, work best with the given situation and weapons. Sometimes it's a better idea to absorb the attack so you can parry the next, stronger one, or another enemy. Enemies don't have identical stagger limits or stagger animation durations, even for their own attacks (different attacks cause different staggering animations when they are parried, test this with golems).

Currently there is only one shield in the game which confers a special effect: Serpent scale shield reduces piercing damage received, even if you don't actually block with it. However, its low block armor is rather insufficient for the current late-game biomes. It's a better idea to go in with higher-end tower shield (or other type) and the root harnesk instead (just mind the fire vulnerability).