This suggestion will consist of a few different aspects, pulled from a couple of suggestions that will be linked below.
Missing Items on Pages:
Starting simply, this is an overall tidy up of the pages. Currently there is a fair few pages that have items either missing or located in other spots with a brief list below:
Bosses:
Dagganoth Kings - Add Mud Battlestaff to this page.
Kalphite Queen - Remove the Onyx as the Kalphite Queen does not drop this and add Dragon 2H Sword to this page.
King Black Dragon - Removal of all Dragon items as the King Black Dragon does not drop these (the majority can be moved across to Graetoriax the Unbroken).
Nomad - Add Zimberfizz and Vagabond to this page.
Tormented Demons - Add Tiny TD to this page.
Skotizo - Add Uncut Onyx to this page.
WildyWyrm - Add Flamey to this page.
Zulrah - Add Pet Snakeling and Uncut Onyx to this page.
Minigames:
Runespan - Add Rune Pouch to this page.
Other:
Slayer Drops - Add Mudskipper Hat, Flippers, Brine Sabre, Granite Helm, Granite Platebody, Granite Platelegs, Granite Shield, Bronze Boots, Iron Boots, Steel Boots, Black Boots, Mithril Boots, Adamant Boots, Rune Boots, Dragon Boots, Uncharged Trident, Kraken Tentacle, Dragon Chainbody, Mystic Hat (Light), Mystic Robe Top (Light), Mystic Robe Bottom (Light), Mystic Gloves (Light), Mystic Hat (Dark), Mystic Robe Top (Dark), Mystic Robe Bottom (Dark), Mystic Gloves (Dark), Infinity Hat, Infinity Top, Infinity Bottoms, Infinity Gloves, Infinity Boots to this page.
TzHaar (New Section) - Add Obsidian Cape, Toktz-Ket-Xil, Toktz-Xil-Ak, Toktz-Xil-Ek, Toktz-Xil-Ul to this page.
Boss Pets - Add Tiny Kree to this page.
Skilling Outfits - This section will only be included if the suggestion attached gets implemented into the game
Marking Completed Logs as Green:
A simple suggestion here, once a section of the Collection Log has been fully completed (let's say Slayer Drops for example), the text on the left side to select the tab will appear as green, with the number within the page also appearing as green (so Obtained: 13/13 within the Slayer Drops tab will have green numbers).
Overall Completed Tally:
Another simple suggestion, where the header at the top lists the Collection Log title, I'm requesting a tally of all the items in the log and how many you have currently achieved.
For any additional updates or content to include, I recommend checking the OSRS Wiki located here - https://oldschool.runescape.wiki/w/Collection_log
Alphabetical Arrangement:
Once again another simple suggestion, re-arranging the tabs within the Bosses section to run in alphabetical order. This will make locating specific tabs much easier.