Given the name Guto, suggestions for a sibling's name could explore several avenues:

Similar Sound/Style: If you like the sound of Guto, which has a Welsh origin and a strong, slightly unusual feel, consider names with similar sounds or a similar number of syllables. Examples include:

• Similar Sounds: Ludo, Cato, Tito, Bruno, Mateo, Rhys (another Welsh name)

• Similar Syllable Count: Owen, Iago, Milo, Leo, Ethan

Complementary Styles: Guto is a strong, somewhat uncommon name. You could balance this with a name that is:

• More Classic/Traditional: William, Charles, Arthur, Thomas, Edward

• More Modern/Simple: Finn, Kai, Liam, Noah, Owen (again, a good option)

• Similar Origin (Welsh): Aled, Dafydd, Ieuan, Llyr, Siôn

Considering Mabon: Mabon is a Welsh name associated with mythology. To complement it, you could choose a name that:

• Shares a Welsh Origin: (See suggestions above) This creates a cohesive feel.

• Has a Nature/Mythological Theme: Orion, Atlas, Apollo, River, Forest

Considering Gender: The provided names don't specify gender. The suggestions above work for both boy and girl names, depending on the specific choice. If you specify the gender of Guto and Mabon, more tailored suggestions can be given.

Ultimately, the best sibling names are those that you and your partner love. This list provides a starting point; explore these options and others that resonate with you. Consider saying the names aloud together to see how they flow and feel.