Bloomberg Terminal (only available in the Bruno Library OR the Bashinshy Lab)
Click advanced search and enter "Agreement and Plan of Merger" (with quotes) in the search box. If you are looking for a specific transaction, you can also enter the name of the target or acquiror in the Company box.
Relevant document types for U.S. deals will include: 8-K's for deal announcements; DEFM 14A, S-4 and 424B3 for merger proxies; SC14D9 for tender offers. For the Merger Agreement, look in EX 2.1 of the 8-K at announcement or Annex A of the subsequent proxies