Wash the baby potatoes thoroughly without removing the skins. Place them in a pot of water and bring to a boil. Simmer until just fork-tender, then drain and allow them to cool slightly before skewering.
While the potatoes cook, wash and cut the remaining vegetables into similar-sized pieces. Keeping the pieces uniform helps everything cook evenly on the grill. Trim mushroom stems if desired and remove seeds from the bell peppers.
If using bamboo skewers, soak them in water for at least 15 minutes. This simple step helps prevent the skewers from burning while grilling. Metal skewers can be used without soaking.
In a bowl, whisk together avocado oil, lemon juice, maple syrup, herb seasoning, salt, and pepper. Stir until everything is well combined. The sauce should have a balanced sweet and tangy flavor.
Thread potatoes, mushrooms, tomatoes, peppers, onions, zucchini, squash, and pineapple onto the skewers. Alternate colors and ingredients for an attractive presentation. Arrange them tightly enough to stay secure but not overcrowded.
Place the assembled skewers on a tray and generously brush them with the maple mixture. Make sure all sides receive some of the glaze. Reserve extra sauce for basting during grilling.
Preheat the grill to medium-low heat, around 400°F. Place the skewers directly on the grill grates and cook for about 3 minutes before turning. Continue rotating and brushing with sauce until the vegetables are tender and lightly charred.
Remove the skewers from the grill once everything is cooked through. Let them rest for a couple of minutes before serving. Enjoy them warm as a main dish or side.