Which ink/toner does the Brother MFC-L3770CDW use?

The Brother MFC-L3770CDW (laser, 2019) uses TN-227BK, TN-227C, TN-227M, TN-227Y, TN-223BK, TN-223C, TN-223M, TN-223Y.

Compatible cartridges

CartridgeColorYieldPagesOEM priceCost/page
TN-227BK black XL3000 $78.00 2.6¢ OEM · AmazonCompatible
TN-227C cyan XL2300 $73.00 3.2¢ OEM · AmazonCompatible
TN-227M magenta XL2300 $73.00 3.2¢ OEM · AmazonCompatible
TN-227Y yellow XL2300 $73.00 3.2¢ OEM · AmazonCompatible
TN-223BK black standard1400 $56.00 4.0¢ OEM · AmazonCompatible
TN-223C cyan standard1300 $53.00 4.1¢ OEM · AmazonCompatible
TN-223M magenta standard1300 $53.00 4.1¢ OEM · AmazonCompatible
TN-223Y yellow standard1300 $53.00 4.1¢ OEM · AmazonCompatible

XL/high-yield cartridges usually cost more upfront but lower the cost-per-page — better if you print often.