Microsoft released cumulative updates and Service Packs. The final SP3 for SQL Server 2016 (build 13.0.6300.2) is the most stable and secure. You can download the SP3 slipstreamed ISO from the same channels above.
This is the most reliable source for the Standard Edition ISO. If you or your organization has a subscription, you can find the 64-bit ISO under the "Downloads" tab by searching for "SQL Server 2016 with Service Pack 3." Microsoft Volume Licensing Service Center (VLSC): sql server 2016 standard edition download 64-bit iso
Malicious actors sometimes distribute fake ISOs with malware. Always verify. Microsoft released cumulative updates and Service Packs