It depends what you find comfortable. I'll link a few examples found on Amazon for ease of searching many things at once:
https://www.amazon.com/Left-Handed-Right-Handed-Handwriting-Correction-Kindergarten/dp/B093DLM612/ref=sr_1_4?crid=2NVD24GAN7D7N&keywords=adapted+writing+utensils&qid=1686282515&sprefix=adapted+writing+utensils%2Caps%2C111&sr=8-4
https://www.amazon.com/Super-Arthritis-Black-Extra-Refills/dp/B00JI6DIAQ/ref=sr_1_6?crid=2NVD24GAN7D7N&keywords=adapted+writing+utensils&qid=1686282591&sprefix=adapted+writing+utensils%2Caps%2C111&sr=8-6
https://www.amazon.com/Special-Supplies-Cushioned-Handwriting-Left-Handed/dp/B08K3M4BPK/ref=sr_1_7?crid=2NVD24GAN7D7N&keywords=adapted+writing+utensils&qid=1686282616&sprefix=adapted+writing+utensils%2Caps%2C111&sr=8-7
https://www.amazon.com/PenAgain-Pack-Pens-GREEN-00063/dp/B002KNHQP2/ref=sr_1_9?crid=2NVD24GAN7D7N&keywords=adapted+writing+utensils&qid=1686282637&sprefix=adapted+writing+utensils%2Caps%2C111&sr=8-9
https://www.amazon.com/Galagee-Reusable-Squishy-Pencil-Handwriting/dp/B09QKDH5K3/ref=sr_1_15?crid=2NVD24GAN7D7N&keywords=adapted+writing+utensils&qid=1686282670&sprefix=adapted+writing+utensils%2Caps%2C111&sr=8-15
https://www.amazon.com/Classics-Triangle-Pencil-1-75-Inch-TPG-16212/dp/B00FQQRRIQ/ref=sr_1_84?crid=2NVD24GAN7D7N&keywords=adapted+writing+utensils&qid=1686282776&sprefix=adapted+writing+utensils%2Caps%2C111&sr=8-84