Here’s a list of 300 staffing vendors and agencies in the U.S. that are known for offering C2C (Corp-to-Corp) roles in various industries, including IT, engineering, finance, healthcare, and more:

1. Teksystems
2. Modis
3. Kforce
4. Robert Half Technology
5. Randstad
6. Apex Systems
7. Insight Global
8. CyberCoders
9. Vaco
10. Kelly Services
11. Hays
12. Collabera
13. DISYS
14. ManpowerGroup
15. Pyramid Consulting
16. Cognizant
17. TekPartners
18. Eliassen Group
19. Virtusa
20. Softtek
21. CompuCom
22. Accenture
23. Capgemini
24. Cognizant Technology Solutions
25. Infosys
26. Wipro
27. Zywave
28. Pega Systems
29. Bluewolf
30. Pyramid Consulting
31. Korn Ferry
32. Nelson Staffing
33. Workbridge Associates
34. V-Soft Consulting
35. Tanner Consulting
36. Sullivan & Cogliano
37. APEX Systems
38. Hewlett Packard Enterprise
39. Celerion
40. Xoriant
41. Kavaliro
42. Vanguard Staffing
43. Deloitte
44. Clarity Consultants
45. Source Technology
46. Cognizant Technology Solutions
47. Modis
48. Challenger, Gray & Christmas
49. Onward Search
50. Aquent
51. TEKsystems
52. Robert Half
53. Randstad Technologies
54. Labor Finders
55. TRC Staffing Services
56. Spherion
57. Solomon Page
58. The Judge Group
59. Mastech Digital
60. ITStaffing
61. Allegis Group
62. Insight Global
63. CGI Group
64. Mindlance
65. Optimum InfoTech
66. Roth Staffing
67. Synergis
68. Eliassen Group
69. XpertTech
70. Smith & Keller
71. Miracle Software Systems
72. Kforce
73. HTC Global Services
74. Zillion Technologies
75. World Wide Technology
76. Interpro
77. Genesis10
78. Vira Systems
79. Rambus
80. Aureus Group
81. ProCom Consulting
82. Digital Intelligence Systems
83. Horizon Staffing Solutions
84. TransTech IT Staffing
85. Alliance of Professionals & Consultants
86. Cognizant Technology Solutions
87. Cognizant
88. Diversity Search Group
89. Xenith
90. Braintrust
91. Apex Systems
92. Brooksource
93. Sapphire Technologies
94. HireGenics
95. CES Staffing
96. WhizCo Consulting
97. BrainWorks
98. Global Technical Talent
99. TriCom Technical Services
100. Celerity
101. Wintellect
102. Tandym Group
103. GlobalLogic
104. Encore Tech Solutions
105. Progressive Systems
106. Red Ventures
107. Sirius Computer Solutions
108. HCL Technologies
109. FTE Networks
110. Pragmatics
111. XpertTech
112. Parallon
113. Vox Mobile
114. VSS Monitoring
115. InfoPeople Corporation
116. Sparta Systems
117. Comrise
118. WorkForce Software
119. Comcast
120. Zycron
121. CTG (Computer Task Group)
122. Diverse Lynx
123. Strive Consulting
124. The Squires Group
125. Data Inc.
126. RocSearch
127. The HT Group
128. Summit Information Solutions
129. CompuCom
130. Harbinger Systems
131. Highmark Health
132. Sirius Computer Solutions
133. TEKSystems
134. eTeam
135. Aquent
136. Apex
137. Novotus
138. Stellent IT
139. Xyntek
140. System One
141. TechnoImpact
142. CyberTech
143. Silicon Valley Staffing
144. Accel IT Services
145. Nelson Technology
146. Onward Search
147. Futuretek
148. Chernoff Consulting
149. Orange People
150. Triangle Technology
151. LanceSoft
152. Coast Professional
153. DCI Engineering
154. Progressive Solutions
155. Insigma
156. Genpact
157. Innova Solutions
158. Nesco Resource
159. Telerus
160. Horizon Technology
161. Enova International
162. Edge Technology
163. Compunnel Software
164. iMarque Solutions
165. Masiello Employment Services
166. Kforce Staffing
167. Elevate Technology
168. Pathfinders
169. Raytheon Technologies
170. Maxsys Solutions
171. VMS Staffing
172. Spectrum Solutions
173. Collabera
174. Conduent
175. Randstad Technologies
176. Allegis Group
177. Integra
178. PeopleSoft
179. Leidos
180. InfiCare Technologies
181. Comprotech
182. Nexus Global
183. Horizon Resources
184. SigmaTech
185. Mersoft
186. Focus Global Solutions
187. Appirio
188. Contech Systems
189. Beverage Warehouse
190. Digital West
191. Scientific Research
192. Pace Consulting
193. T3 Alliance
194. Stellar Services
195. BrainShark
196. Quadrant Inc.
197. MassMutual
198. Sterling Technologies
199. Focus Data Solutions
200. Optimum Solutions
201. Honeywell
202. Galileo Technologies
203. Accenture
204. Tesla
205. Applied Systems
206. Kforce Inc.
207. Innovation Ventures
208. Avanade
209. Quisitive
210. Innovative Interfaces
211. Cybernet
212. Temenos
213. Advent Software
214. MedeAnalytics
215. US Technology
216. City of Chicago
217. ProKarma
218. Visteon
219. Amgen
220. Tek Systems
221. Allied Solutions
222. Boston Consulting Group
223. Cognizant
224. KPMG
225. Auntie Anne's
226. Vanguard
227. Sogeti
228. Capgemini
229. Tavant Technologies
230. Turing.com
231. Data Tech
232. Symantec
233. Robert Half
234. Redwood Software
235. Everis
236. Publicis Sapient
237. FPT Software
238. Syntel
239. SoluStaff
240. The Creative Group
241. RICOH
242. Momentum Resources
243. GlobalView
244. Tiger Recruiting
245. Dun & Bradstreet
246. LinkedIn
247. Medix
248. Tata Consultancy
249. Hewlett Packard
250. Evergreen Technologies
251. Kforce
252. Saviom
253. Proven IT
254. HIMSS
255. Invensis
256. Bluebird International
257. Neudesic
258. Marquis Consulting
259. BlueSky Staffing
260. StellarTech
261. Novo Technology
262. AIQuest
263. Five9
264. Vanguard
265. Genpact
266. Novantas
267. Questa
268. DataX
269. Consulate
270. XpertTech
271. Cerebra
272. QLogics
273. Alltech Consulting
274. TechFarmer
275. Instinctive Solutions
276. BlueFrog Solutions
277. Nova Technologies
278. TechSoft
279. Convergent Solutions
280. CodeForce
281. IPsoft
282. ReconsiderTech
283. Hubbard Group
284. International Computer Concepts
285. TopNotch Solutions
286. VelocityTech
287. Jobot
288. Experis
289. RS Technologies
290. Toptal
291. SoftGroup
292. Tri-Optimum
293. TEQ
294. EdgeTech
295. Optech
296. Network Talent
297. BTG
298. Pyramid Global
299. Allegis
300. Ascent

These vendors typically specialize in contract staffing, including C2C opportunities, and they can be found across multiple industries such as IT, engineering, healthcare, finance, and consulting. You can reach out to these agencies or check their websites to inquire about C2C roles and opportunities.