To start, you’ll need to craft yourself an excludifier. This takes an ender pearl, so don’t expect to have one right when you start!
After you have your excludifier, simply right click with it to bring up this GUI:
The first screen will show your inventory on the bottom and which items you have selected on top. To go to the creative-like search, simply click the compass tab to open a GUI similar to the creative inventory. In here, simply left click items to select or deselect them:
Once you’ve selected a few items, you can go back to the first tab and your selected items will be displayed. Note that you can also drag items from your inventory to the top section to select them. This will be required if you are your server admin decides to disable the creative-like search:
And you’re done! Now you won’t pick up any of those items until you either remove the excludifer from your inventory or deselect the items. Excluded items are saved in the item’s NBT data, so you can share your excludifers with another person or have multiple excludifiers in your inventory at once!
Note that you type in text to search for an either tab to filter your results: