Huge pull requests won't load in 1 chunk, so the script misses additional containers.
Also it's tedious to click all the diffs that weren't loaded and expanded.
Here's an update I'm using:

// ==UserScript==
// @name         Hide Annoying BitBucket Diffs 
// @namespace    http://sagegerard.com
// @version      0.1
// @description  Hides bulky diff blocks for autogenerated files in BitBucket pull requests using RegExp patterns defined by clear-text resource
// @author       Sage Gerard
// @match        https://*.bitbucket.org/*/pull-requests/*
// @resource     ignorePatterns https://pastebin.com/raw/MTTktsuE
// @grant        GM_getResourceText
// ==/UserScript==

/*
.*meta$
.*prefab$
.*unity$
.*asset$
.*anim$
.*controller$
.*png$
.*tpsheet$
.*spriteatlas$
*/

(function() {
    'use strict';

    var timer = setInterval(function() {
        const diffBlocks = document.getElementById('changeset-diff').querySelectorAll('.iterable-item');
        const len = diffBlocks.length;

        const textSource = GM_getResourceText("ignorePatterns");

        if (!textSource) {
            console.log('[HABD] Could not load ignore patterns to hide BitBucket diffs, or no patterns were defined. Check your resource?');
            return;
        }

        const patterns = textSource.split(/\r?\n/).map((pattern) => new RegExp(pattern));

        if (len > 0) {
            for (let i = 0; i < len; ++i) {
                const db = diffBlocks[i];
                const filename = db.getAttribute('data-identifier');

                if (patterns.some(re => re.test(filename))) {
                    db.remove();
                    console.log('[HABD] Removed diff block for ', filename);
                }
                else {
                    var tryAgain = db.getElementsByClassName('load-diff');
                    if (tryAgain.length > 0) {
                        tryAgain[0].click();
                    }
                }
            }

            //clearInterval(timer);
        }

    }, 500);
})();