1-appricatation on small achievements by thanku card
2-Birthday celebrations on monthly basic
3-working anniversary, wedding anniversary, birthday congratulation mail to all.
4-on same day of birthday you can give some gift just like card, pen, chocolate etc.
5-On wedding anniversary, you can give some gifts like mug, movie ticket, lunch coupon etc.
6-On working anniversary, you can plan some milestone just like 5 year,10 year ,15 y ear and celebrate with all senior staff on same day with some gifts or some cash amount.
7-Plan for some outdoor activities as a HR for all employees.
TEI is very wide area but if its your starting in this area you can start with above mentioned small small activities.