Voluntary Day Off assignments (VDA) pays 200%, you put yourself on a list and scheduling calls in seniority order when they have a trip that needs to be covered. Report time can be 1hr, or 10hrs away. Call often goes like this:

CS: "How quick can you get to the airport?"
Pilot: "Umm, about 2hrs"
CS: "Ok, we're bypassing you and going to find someone who can get there faster *click*

Most super senior guys drop their whole month (give it away via the tradeboard) and mark themselves VDA for the whole month and clean house flying 200% every day.

The other option is Premium trips. These are picked up in Flica first come, first served. CS marks a trip as PREM when they feel like it and pilots can then pick it up for 150%. Trip might be 3hrs from now, might be tomorrow, no limits on report time. Often times CS is too lazy to mark it as PREM and they skip right to calling VDAs.

One other option is RSA (I forget the acronym, Reserve System Augmentation or something). CS sends an email advertising extra SCR RAPs for pickup via flica first come first served. Lineholders or RSVs can pick these up. Each SCR RAP pays 4.2hrs @ 150%, or if you fly during that RAP you get the value of the trip @ 175%.

Reserve pilots are eligible for VDA, PREM, and RSA trips. All go above the 75hr guarantee.

One big difference I noticed reading the NK contract is lineholders lose access to opentime within 2 days (Edited: previously thought it was 3) from report time where JB can ADD/SWAP trips from Flica up to 3.5hrs before report time. Weather rolls through, lots of broken pairings start dropping in and guys swap/add trips for easy soft time. It helps the company too because there's no way we'd have enough staffing to cover the IROPs with RSV pilots only. They need lineholders to come pick up the easy stuff too.