UPDATED VERSION PER APRIL 2020
On this page you will find some leaders for download. After seeing people search for leaders on various forums, I decided to share the ones I built.

01. SMPTE/Academy/FrameCounting Leader
JtB_StartLeader_1920x1080_R709_2020_UPDATED001
CLICK THUMBNAIL TO DOWNLOAD
— Let me know if you like and/or use these via siteinfo at terburg dot com.

This leader features three clocks. It counts down as 8secs@24fps (SMPTE) as well as 12ft@35mm (Academy) and it has a total frame counter (192), with a sync mark at -48frs (02sec@24fps/03ft@35mm) before First Frame Of Action (FFOA).

N.B. You can download and use it, but you are not allowed to alter it in any way, especially length. Traditionally, even 25fps film projects would use this leader, 192 frames in length, either counting SMPTE (8 seconds measured at 24fps) or Academy (12 feet of 35mm 4-perf). In 25fps projects, the leader should be run 1 frame by 1 frame (so it will run faster). Sync mark (2-pop or 3-pop) remains at the same position, 48 frames before FFOA, regardless of film speed*.

* When you splice in the leader at the head of your sequence, you will find that if the PICTURE START mark is at 0xh00m00s00f, then the sync mark is at24TC 0xh00m06s00f and 25TC 0xh00m05m19f, and the FFOA occurs at 24TC 0xh00m08s and 25TC 0xh00m07s17f.

The download is a 1920x1080 image sequence (TIF 16bit), with studio swing (legal) levels. When importing, choose "Do not modify, treat as legal range", and tick the box that says "Autodetect Sequentially-Numbered Files".
importsequential
Version history: Originally there was only an SD version, at the end of July 2009 I rebuilt it in HD. In April 2020, I did an update, changing the size of the center clock so it will now fit inside a 2.39:1 'scope' mask, I rerendered everything with the HDTitleFilter turned off, tweaked the placement and size of the two smaller clocks, redid some of the typography, added reference bars to the sides of the second second of the leader.
  
02. END OF REEL

For a simple tail pop, you can use this sequence.
JtB_EndOfReel_1920x1080_R709_001

03. 40-Second Countdown Clock 
Intended for (Broadcast) Master Tapes (or file based delivery). Starts 40 seconds before FFOA. Usually should run no further than T-3 seconds (verify specs with your broadcaster). To the right, there's plenty of room to add a slate with data such as Program Title, Client, Episode/Version, Duration, Sound Mix etcetera. It's only 40 frames long, you'll need to slow the playback speed down to 1 (one) fps.
 
countdown-2 click for preview Download   
For those who are curious, these were all made entirely on an Avid, using nothing but the traditional Title Tool and the 3D DVE, working in Uncompressed 10-bit 1920x1080 progressive HD. Let me know if you use and/or like them at siteinfo at terburg dot com.