Anselm Joseph (Of St. Patricks High School) as done a wonderful job of collecting old & new names of various streets & roads of Karachi:- There are more if you know please add in the comments:
These are:-
Old Names – New Names:-
Atmaram Street -Bagh-e-Zohra Road;
Barnes Street -Jamila Street;
Bonus Road -Fatima Jinnah Road;
Bunder Road -M. A. Jinnah Road;
Burnes Road -Mohammad Bin Qasim Road;
Clark Street -Shahrah-e-Iraq;
Clifton Road -Khayaban-e-Iqbal;
Commissariat Road- Kiyani Shaheed Road;
Connaught Road- Chaudhry Rehmat Ali Road;
Cowel Road -Sarmad Road;
Drigh Road -Shara-e-Faisal;
Elphinstone Street -Zaibunnisa Street;
Embankment Road- Nawab Mahabat Khan Road;
Frere Road- Shahrah-e-Liaquat;
Frere Street -Dr. Daudpota Road;
Garden Road- Sir Aga Khan III Road;
Gizri Road -Chaudhry Khaliquzzaman Road;
Golf Club Road- McLallan Road;
Grant Road -Hasrat Mohani Road;
Harchandrai Road- Hussain Bhai Bandukwala
Road & Siddiq Wahab Road;
Harris Road -Aga Khan Road;
Havelock Road -Aiwan-e-Sadr Road;
Hiradharam Road -Mohammad Ali Bogra Road;
Hira Lal Ganatra Road- Aslam Road;
Hospital Road -Rafiqui Shaheed Road;
Ingle Road- M.R. Kiyani Road;
Inverarity Road- Sarwar Shaheed Road;
Kattyan Road -Stock Exchange Road;
Kingsway -Shahrah-e-Kamal Ata Turk;
Kutchery Road – Dr. Ziauddin Ahmed Road;
Lawrence Road -Nishtar Road ;
Lidbetter Road- Japani Road;
Mansfield Street -Syedna Burhanuddin Road ;
McLeod Road- I.I.Chundrigar Road ;
Napier Road -Shahrah-e-Altaf Hussain;
Napier Street -Mir Karamali Talpur Road;
Newnham Road -Fakhr Matri Road ;
Preedy Street –
Princess Street- Chand Bibi Road
Queens Road -Moulvi Tamizuddin Khan Road;
Queensway -Shahrah-e-Iraq;
Ramachandra Temple Road -Babar Street;
Rampart Road -Adamji Dawood Road;
Scandal Point Road- Club Road;
Solomon David Road -Suleman Dawood Road ;
Somerset Street -Raja Ghazanfar Ali Road;
Srichand Vishindas Road -Haji Kassim Sommra Street;
Tahilram K. Road -G. Allana Road ;
Udhavdas V. Street -Soomra Gali ;
Victoria Road -Abdullah Haroon Road;
Vishwanath Patel Road- Aslam Road; &
Wood Street -Talpur Road.
OTHER PLACES (Added by AHK 2018)
Jehangir Kothari Parade – Bagh Ibn-e-Qasim
Sangster Road: Ahmad Muneer Shaheed Road
University Road- Jamiluddin Aali Road (2018)
Will continue to add…..AHK
Any photo of the old street sign will be welcome.
Good Old Karachi 
New Queens Road changed to Molvi TammizUddin Khan Road.