The main component of a healthy environment for self esteem is that it needs be nurturing. It should provide unconditional warmth.
"I thank you all from the bottom of my heart; you have shown what we are capable to delivering together. I appreciate your responsiveness, sense of responsibility and overall technical expertise."
"You really moved fast on that. Sure appreciate it. We will have some assets configured and ready for you by Monday."
"It has been great pleasure working with you and your team. We wouldn't have completed our hibernate project well ahead of our goal without your contribution. I have thoroughly enjoyed working with you and admired your technical knowledge and approach to problem solving."