According to Official Guinness Records,
The most laptops toppled in a domino fashion is 520 and was achieved by Lenovo BT/IT (China) in Beijing, China, on 27 April 2018.The record was achieved as part of a team building project of LENOVO BT/IT for their new financial year kick off event. There were more than 1,300 people taking part in the event to place 45,000 dominoes, within which, the laptops were placed as part of the topple.
For a complete list of 2018 records, please visit 2018 Guinness Records in China.