Live top-trending board for exactly one feed type. No keyword. For 'Amazon Best Sellers by Category', 'Google Trends by Category', 'Top Websites', 'Substack by Category', and 'TikTok Trending Hashtags by Category', category selects the board. Default sort is current rank. Use sort='rank_change' for climbers vs a prior snapshot (window 1d, 3d, 7d, 14d, or 30d). If the requested board is not in the database yet (for example a country that is not collected on the schedule), the board is fetched live. App Store Top Free, App Store Top Paid, and Google Play are live store boards, not keyword lookups. App history is available via get_growth or get_time_series with source app downloads or app rankings and an Android bundle ID. Live boards are only available here, not via get_time_series. Returns a plan-limit message when the request is rate limited or the monthly quota is used up.