I saw the following 53 aircraft at London Heathrow on Monday, June 17, 2019:
9V-SKU A380-841 Singapore Airlines
A6-APA A380-861 Etihad Airways
A6-APE A380-861 Etihad Airways
C-FVLX 787-9 Dreamliner Air Canada
EC-JGS A321-211 Iberia
G-BYGA 747-436 British Airways
G-BYGC 747-436 British Airways
G-CIVA 747-436 British Airways
G-CIVB 747-436 British Airways
G-CIVE 747-436 British Airways
G-CIVU 747-436 British Airways
G-CIVY 747-436 British Airways
G-EUOA A319-131 British Airways
G-EUOC A319-131 British Airways
G-EUPE A319-131 British Airways
G-EUPF A319-131 British Airways
G-EUPM A319-131 British Airways
G-EUPS A319-131 British Airways
G-EUPZ A319-131 British Airways
G-EUUB A320-232 British Airways
G-EUXF A321-231 British Airways
G-EUXJ A321-231 British Airways
G-EUXL A321-231 British Airways
G-EUYA A320-232 British Airways
G-EUYE A320-232 British Airways
G-EUYS A320-232(WL) British Airways
G-MEDU A321-231 British Airways
G-STBC 777-36N(ER) British Airways
G-STBL 777-336(ER) British Airways
G-TTNE A320-251N(WL) British Airways
G-TTNI A320-251N(WL) British Airways
G-VIIA 777-236(ER) British Airways
G-VIIC 777-236(ER) British Airways
G-VIIG 777-236(ER) British Airways
G-VIIN 777-236(ER) British Airways
G-XLEH A380-841 British Airways
G-XLEL A380-841 British Airways
G-YMMJ 777-236(ER) British Airways
G-ZBJH 787-8 Dreamliner British Airways
G-ZBKA 787-9 Dreamliner British Airways
G-ZBKD 787-9 Dreamliner British Airways
G-ZBKE 787-9 Dreamliner British Airways
G-ZBKM 787-9 Dreamliner British Airways
N26906 787-8 Dreamliner United Airlines
N271AY A330-323 American Airlines
N724AN 777-323(ER) American Airlines
N725AN 777-323(ER) American Airlines
OD-MED A330-243 MEA - Middle East Airlines
OO-ABB A340-313 Air Belgium
VN-A862 787-9 Dreamliner Vietnam Airlines
VT-ALQ 777-337(ER) Air India
VT-ANR 787-8 Dreamliner Air India
ZS-SNC A340-642 South African Airways