Any and all of the photocopy papers of the following paper companies will be alkaline. All of them make one or more high quality copy papers, and four of them (Boise Cascade, Hammermill, Island Paper and Weyerhaeuser) also make commodity (inexpensive) grades.
Boise Cascade
Byron Weston
Eastern
Finch Pruyn
Hammermill
Island Paper
Rolland
Weyerhaeuser
The following companies make one or more alkaline photocopy papers. Since they also make acid paper, it may be necessary to test the paper's pH before making a purchase, unless the sales agent is knowledgeable about acid and alkaline.
Gilbert
International Paper
James River
Lincoln
The first three companies make high quality copy papers, James River and Lincoln make commodity grades.