Many of these were in the June 27th rule. All took effect during 2018.
1) Use of an ATD for instrument proficiency, which until this year was required every two months, is now required only every six months. This aligns the ATD recurrency requirement with other IFR proficiency methods, lowers proficiency cost and encourages use of ATDs in flight training. (CFR 61.57c).
2) Sport pilot training can now be credited toward higher certificates or ratings, again reducing the cost of certification for pilots working on advanced certificates and ratings. (CFR 61.99; 61.109l).
3) Pilots may now gain recurrency in an ATD, FFS or FTD without having the pay for a CFI in attendance. (CFR 61.51g).
4) Technically advanced airplanes may now be used in the place of complex (gear, flaps and prop controls) airplanes for the 10 hours of time and checkrides required for new commercial pilot applicants and CFI applicants. This change relieved both flight schools and applicants, since complex aircraft have become both scarce and expensive. The FAA estimates savings of $2.8 million over five years. CFR 61.1, 61.129a3ii, appendix D to Part 141, and 61.31e,f) AOPA