As a Day Trader horizontal Support and Resistance from the current and the prior day (HOY, LOY and COY) are your main concern.
On instruments with RTH (regular trading hours) you often have gaps on a chart, that stay open for more than a day.
A couple of times a month these open gaps from prior days (further back than yesterday) also play an obvious role as support or resistance on the intra-day chart.
These open gaps often act as a magnet and price gets drawn to these levels.
If such a support level is broken it often becomes a new resistance level and vice versa.
We’ve added the “Support/Resistance Open Gaps” indicator to our portfolio of free indicators.
It shows open as well as closed gaps from prior days, so it’s possible to do some easy back testing too. You can find it in our free indicators section.
Here are a couple of examples from the recent past (all charts are 5 min E-mini RTH with a small daily inset chart).